assessment of air-borne particulate matter (pm ) and...
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ASSESSMENT OF AIR-BORNE PARTICULATE
MATTER (PM2.5) AND BIO-AEROSOLS IN DIFFERENT
RESIDENTIAL BUILT MICRO-ENVIRONMENTS OF
LAHORE, PAKISTAN
THESIS SUBMITTED FOR THE PARTIAL FULFILLMENT OF THE PhD DEGREE IN
ZOOLOGY
By
Sidra Safdar
Roll # ZP11-16
Session 2011-onwards
Under the Supervision of
Dr Zulfiqar Ali
ENVIRONMENTAL HEALTH AND WILDLIFE
DEPARTMENT OF ZOOLOGY
UNIVERSITY OF THE PUNJAB
QUAID-E-AZAM CAMPUS, LAHORE
In the name of Allah, the Most Merciful, the Most Beneficent
CERTIFICATE OF APPROVAL
This is to certify that the experimental work described in this thesis submitted by Sidra Safdar
has been carried out under my direct supervision. I have personally gone through the raw data
and certify the correctness/authenticity of all results reported herein. I further certify that this
data has previously not been submitted as a partial or complete requirement for the fulfillment
of award of any other degree from any other institution at home or abroad. I endorse its
evaluation for the award of PhD degree through the official procedures of the University.
.
________________________
Supervisor
Dr Zulfiqar Ali
Associate Professor
Department of Zoology
University of the Punjab
Quaid-e-Azam Campus
DEDICATION
To my beloved Father (Late) for whom it was a dream come true; I
wish he would have lived a little longer to see me complete my
doctorate
&
To my loving Mother who encouraged me at every step and has
been a constant source of hope and motivation for me
i
ABSTRACT
The situation of air quality is worse in the developing countries where annually million
lives are lost as a result of impaired air quality which stems from poor socio-economic
conditions and lack of awareness. Although a few studies have been conducted regarding air
pollution monitoring in Pakistan, no baseline data has been generated to gather information
about the indoor air quality. Besides this, there is yet no practical implication to reduce and/or
remove the load of pollutants present in the air. Moreover, the studies conducted so far have
limited their focus on aerosol emissions from biomass burning and the associated health
outcomes in rural areas. So far any detailed study on the indoor air quality of urban centers in
Pakistan has not yet been reported.
Particulate matter and bioaerosols are two of the most important components of the air
we breathe as both of these are ubiquitous in the air. Many studies have reported a number of
negative health outcomes owing to a prolonged exposure to these two pollutants and their
synergistic effect is also documented to be detrimental for human health.
Keeping in view the insufficient data regarding the concentration of fine particulate
matter and bioaerosols in the indoor air of urban centers in Pakistan, the current study was
designed to monitor the air quality of indoor micro-environments of residential houses (n = 30)
of Lahore, Pakistan. The parameters monitored were fine particulate matter and bio-aerosols.
PM2.5 was monitored using DustTrak aerosol monitor (model 8520, TSI Inc.) while Koch
sedimentation method was employed for microbial sampling. The kitchens and living rooms
were identified as two major micro-environments of any residential household and thus were
marked to be monitored at each of the selected sites. The ventilation rates were also measured
using the tracer gas method with carbon dioxide as the tracer gas. PM2.5 monitoring was carried
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out for 72 hours each with both micro-environments being monitored in parallel while agar
coated Petri plates were exposed for twenty minutes at each location to collect the bacteria and
fungi suspended in the air settling by gravity. Temperature and relative humidity were also
noted during bio-aerosol sampling.
Our results were indicative of poor air quality in the residential indoor environments of
Lahore. The 24-h average PM2.5 levels at any of the monitored site were manifolds higher than
the WHO recommended limits of 25µg/m³. Overall, the mean levels of fine particulate matter
exceeded 13 times the WHO limits. It was observed that cooking, cleaning, movement of
people, space heating (during winters) and smoking (in some houses) were the principal indoor
sources of particulate pollution. Maximum and minimum air change rate per hour (ACH) was
determined for each micro-environment to observe the influence of ventilation on the indoor
air quality and was observed to have a significant impact upon PM levels. Low ventilation
rates during winter season as well as meteorological factors resulted in elevated PM levels
indoors during the colder months. The exposure risk of the inhabitants, most particularly
women and small children, was greatly increased as they spent maximum time indoors.
The micro-biota of the sampled sites was comprised of common genera which were
also identified as opportunistic pathogens. The bacterial composition was consisting of seven
species including Micrococcus spp., Staphylococcus spp., and Bacillus spp., with occasional
record of Serratia spp. Among the eleven fungal species identified, the dominant ones were
Alternaria alternata and Aspergillus spp., with Trichoderma, Mucor, Fusarium and Rhizopus
also detected in less numbers. The colony forming units per cubic meter for bacteria ranged
from 472 to 9,829 in the kitchens and from 275 to 14,469 in the living rooms. Likewise, the
fungal cfu/m3 ranged between 234 and 1887 in the kitchen and from 314 to 1887 in the living
iii
room. A seasonal variation in bioaerosols was evident in the kitchens while being not so
pronounced in the living rooms. Linear regression model exhibited a direct association of
temperature with bacteria and fine particulate matter but not with fungi. Out of thirty monitored
households, sixteen contained at least one individual with allergic reactions from dust or during
wheat harvesting season. These findings highlight the enhanced risk of exposure to fine
particulate matter as well as bioaerosols in the urban residential built environment in Pakistan.
The study holds its significance in being the first of its kind as previously no data
focusing on simultaneously measured PM and bioaerosol levels in the urban centres of Pakistan
has been reported. With the lack of any definite policies, the area of indoor air quality has been
ignored at large. It is recommended that more detailed studies must be conducted to monitor
air quality in the built micro-environments and guidelines should be formulated to keep a check
on the contaminant levels indoors.
iv
ACKNOWLEDGEMENTS
First and foremost, glory and praise to ALLAH Almighty who created life and blessed
mankind by bestowing him the power of thinking and wisdom. All and every exaltation is for
the HOLY PROPHET (P.B.U.H) who guided man and enabled us to recognize our Deity.
Though only my name appears on the cover of this dissertation, a great many people
have contributed to its production. I owe my gratitude to all those people who have made this
dissertation possible and because of whom my doctorate experience has been one that I will
cherish forever.
My heartiest and warmest felicitations and obligatory gratitude is to Prof Dr Javed
Iqbal Qazi, Professor and Chairman, Department of Zoology, University of the Punjab
for his kind cooperation. My thanks are also extended to Prof Dr. Muhammad Akhtar, ex-
Chairman, Dept. of Zoology who was always helpful and co-operative.
My deepest gratitude is to my respected supervisor, Dr. Zulfiqar Ali. I have been
amazingly fortunate to have a supervisor who gave me the freedom to explore things on my
own and at the same time the guidance to recover when my steps faltered. Dr. Zulfiqar Ali
taught me how to question thoughts and express ideas. His patience and support helped me
overcome many critical situations and finish this dissertation.
Before I acknowledge anyone else, I am immensely indebted to my previous research
supervisor, Dr Asif Mehmood Qureshi, Principal (Retd.) Govt. Islamia College, Civil
Lines. He was the one who motivated me and pushed me forward in the field of research and
truly taught me what a researcher is. Sir, my endless gratitude towards you cannot pay for what
I have gained from you.
I pay my special regards to Dr Zaheer Ahmad Nasir, University of Cranfield, UK
for imparting devotion, professional guidance and constructive suggestions whenever I was
stuck at anything. Thank you sir for bearing up with me and for your unconditional support
and guidance whenever required.
I am also greatly indebted to Dr Shakil Ahmed, Department of Botany-University
of the Punjab for identification of the fungal species which would have been impossible
otherwise. The guidance and support of Dr Sikander Sultan, Department of Microbiology
and Molecular Genetics-University of the Punjab is also duly acknowledged in
v
identification of bacterial species. In fact the guidance provided by these two teachers cannot
be forgotten which made it possible for me to pass through all hardships during this research.
Next to them I would love to acknowledge full time cooperation and spirit lifting
encouragement of the occupants of the sampling sites where this research was conducted. It
would be unfair not to mention their names and I am greatly indebted to Sana Islam, Sana
Bashir, Hadia Chughtai, Shakil Ahmed, Bushra Nisar Khan, Bushra Ansari, Mubashir
Ahmad, Sadia Razzaq, Sadia, Awais Liaquat, Rafia Kamal Butt, Khadija Qasim Butt,
Kamran, Arslan, Abdullah Baig, Uzma, Noreen, Shaista Kanwal, Muhammad Ijaz,
Muhammad Sajjad, Muhammad Abbas, Zulfiqar Ali, Roohi Ejaz, Maryam, Ambreen,
Ansa Shahzadi, Mehwish, Sehrish Ramzan and Aqsa Qayuum. As a matter of fact it was
heart-warming to experience such a positive response from them, many of them totally
strangers, to allow me to run my instruments (which were somewhat noisy) for seventy two
hours at each house. The people were anxious to learn more about my work and how could
they minimize the exposure risks around them. It was truly an over-whelming and
unforgettable experience for me.
I am obliged by the support and co-operation of Dr Waseem Ahmad Khan who
encouraged me a lot while writing this dissertation. Another person whose thanks is due on me
is Mr. Hassan Ali whose valuable assistance is acknowledged in providing me with the GIS
maps of Lahore and the study locations. Muhammad Nouman, Research officer,
Environment Protection Department, Punjab provided with data on ambient air and I am
greatly thankful to him as well.
Most importantly, none of this would have been possible without the love and patience
of my family. My family, to whom this dissertation is dedicated, has been a constant source of
love, concern, support and strength all these years. I have to give a special mention for the
support given by my brother Muhammad Abubakar without whose help this work would
never have been completed as he acted like my driver throughout this research. My uncles were
also a constant source of inspiration and their unending support to fulfill their late brother’s
dream (my father) was always motivating for me. The support of my husband Qazi
Muhammad Imran is also unforgettable and helped me through tough times.
My friends Sumaira, Rafia, Sana and Aqsa have helped me stay sane through these
difficult years. Their support and care helped me to overcome setbacks and stay focused on my
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doctorate study. I greatly value their friendship and I deeply appreciate their belief in me. My
lab fellows, Nimra Afzal, Anam Zakir, Khadija Aziz and Ahsan Ashraf also have a
noteworthy share in assisting me whenever I needed help and I am grateful to all of them.
Bushra Nisar Khan, Mubashir Ahmad, Zona Zaidi, Zainab Irfan, Syed Turab Raza and
many others were also a motivating force for me whenever I felt down during my work and I
owe them a bundles of thanks for their support.
The research work was funded by HEC Indigenous Ph.D. 5000 Fellowship (vide letter
No.17-5(2Bm1-478)/HEC/Sch-Ind/2012 dated 01.04.2014 and is highly acknowledged.
Sidra Safdar
PIN # 112-23380-2Bm1-478
vii
ABBREVIATIONS
IAQ Indoor Air Quality
US-EPA United States Environmental Protection Agency
Pak-EPA Pakistan Environmental Protection Agency
PM Particulate Matter
VOC’s Volatile Organic Compounds
WHO World Health Organization
CO Carbon Monoxide
CO2 Carbon dioxide
NOx Nitrogen Oxide
Sox Sulphur Oxide
HVAC system Heating, Ventilation and Air Conditioning system
SPM Suspended Particulate Matter
RSPM Respirable Particulate Matter
ETS Environmental Tobacco Smoke
ACGIH American Conference of Government Industrial Hygienists
ASHRAE American Society for Heating, Refrigeration and Air
Conditioning Engineers
NEQS National Environmental Quality Standards
ACH Air Change rate per Hour
Cfu/m3 Colony forming units per cubic meter of air
viii
COPD Chronic Obstructive Pulmonary Disease
RH Relative Humidity
ALRI Acute Lower Respiratory Infections
GDP Gross Domestic Product
OSHA Occupational Safety and Health Administration
AIHA American Industrialist Hygiene Association
ix
TABLE OF CONTENTS
Abstract i
Acknowledgements iv
Abbreviations vii
List of tables x
List of figures xii
Chapter # Title Page #
Chapter One Introduction 1
Chapter Two Literature review 23
Chapter Three Materials and methods 65
Chapter Four Results 76
Chapter Five Discussion 179
References 202
Annexure-I Questionnaire 235
Annexure-II Maximum and minimum air change rate 241
at the sampling sites
Annexure-III Annual Trend of Ambient Air Quality of Lahore 298
Annexure-IV Installation of instruments at sampling sites 299
Annexure-V Seasonal variation of fine particulate matter in 314
residential micro–environments of Lahore,
Pakistan
Annexure-VI Assessment of Airborne Microflora in the Indoor 322
Micro-Environments of Residential Houses of
Lahore, Pakistan
x
LIST OF TABLES
Table 1 Indoor air pollutants and their sources 3
Table 2 Health effects of exposure to bio-aerosols 15
Table 3 Administrative towns of City District Lahore and their population
(Source: GOP, 2014)
67
Table 4 Profile of Category-A sampling sites 83
Table 5 Representative 24-h, hourly maximum and hourly minimum
averages of PM2.5 recorded in the kitchens and living rooms of
category-A sites
84
Table 6 Profile of Category-B sampling sites 107
Table 7 Representative 24-h, hourly maximum and hourly minimum
averages of PM2.5 recorded in the kitchens and living rooms of
category-B sites
108
Table 8 Profile of Category-C sampling sites 131
Table 9 Representative 24-h, hourly maximum and hourly minimum
averages of PM2.5 recorded in the kitchens and living rooms of
category-C sites
132
Table 10 Correlation between PM2.5 levels in kitchens and living rooms of
sampling sites (strong correlations shown in bold)
154
Table 11 Overall PM generation observed during different activities in the
kitchens
158
Table 12a One-way ANOVA for seasonal variation in PM2.5 levels in kitchens 162
Table 12b One-way ANOVA for seasonal variation in PM2.5 levels in living
rooms
162
Table 13 ACH and Air flow rate (liter per second per person) in the kitchens
and living rooms of the sampling sites
165
Table 14 Regression modeling: ACH versus PM2.5 (α = 0.05) 166
Table 15 Temperature, Relative humidity and Total bacterial colony forming
units per meter cube (cfu/m3) present in the kitchen and living room
of each sampling site
168
Table 16 Temperature, Relative humidity and Total fungal colony forming
units per meter cube (cfu/m3) present in the kitchen and living room
of each sampling site
169
Table 17 Colony forming units of each bacterial species identified in the
kitchens and living rooms of the sampling sites
170
Table 18 Colony forming units of each fungal species identified in the kitchens
(K) and living rooms (LR) of the sampling sites
171
Table 19 Regression modeling of different parameters in kitchen (α = 0.05).
Significant results are marked in bold text.
174
xi
Table 20 Regression modeling of different parameters in living room (α =
0.05). Significant results are marked in bold text.
175
Table 21 One-way ANOVA for seasonal variation in bioaerosol levels in the
kitchens and living rooms
177
Table 22 One-way ANOVA for association between bioaerosol levels and
PM2.5 in the kitchens and living rooms
178
Table 23 Sources and health hazards posed by the observed bacterial and
fungal species (Source: Kowalski, 2006).
191
xii
LIST OF FIGURES
Figure 1 Flow of pollutants in an indoor environment 4
Figure 2 Categories of particulate matter according to size 7
Figure 3 Deposition of particulate matter in the various regions of respiratory
tract according to their size
9
Figure 4 Map marking the boundaries of City District Lahore 65
Figure 5 Location of sampling sites in Lahore city 76
Figure 6 Location of sampling sites according to number of occupants [up to
5 occupants (red circles); 6 to 10 occupants (blue circles); 11 and
above (green circles)]
77
Figure 7 Proportion of male and female occupants belonging to different age
groups
78
Figure 8a Number of hours spent by male occupants in the house 79
Figure 8b Number of hours spent by female occupants in the house 79
Figure 9 Time spent by females in the kitchen 80
Figure 10 Floor plan of sampling site A1 85
Figure 11a 24-h representative mean values of PM2.5 in kitchen of sampling site
A1
85
Figure 11b 24-h representative mean values of PM2.5 in living room of sampling
site A1
86
Figure 12 Floor plan of sampling site A2 87
Figure 13a 24-h representative mean values of PM2.5 in kitchen of sampling site
A2
87
Figure 13b 24-h representative mean values of PM2.5 in living room of sampling
site A2
88
Figure 14 Floor plan of sampling site A3 89
Figure 15a 24-h representative mean values of PM2.5 in kitchen of sampling site
A3
89
Figure 15b 24-h representative mean values of PM2.5 in living room of sampling
site A3
90
Figure 16 Floor plan of sampling site A4 91
Figure 17a 24-h representative mean values of PM2.5 in kitchen of sampling site
A4
91
Figure 17b 24-h representative mean values of PM2.5 in living room of sampling
site A4
92
Figure 18 Floor plan of sampling site A5 93
Figure 19a 24-h representative mean values of PM2.5 in kitchen of sampling site
A5
93
xiii
Figure 19b 24-h representative mean values of PM2.5 in living room of sampling
site A5
94
Figure 20 Floor plan of sampling site A6 95
Figure 21a 24-h representative mean values of PM2.5 in kitchen of sampling site
A6 (monitored during Ramadan)
95
Figure 21b 24-h representative mean values of PM2.5 in living room of sampling
site A6
96
Figure 22 Floor plan of sampling site A7 97
Figure 23a 24-h representative mean values of PM2.5 in kitchen of sampling site
A7
97
Figure 23b 24-h representative mean values of PM2.5 in living room of sampling
site A7
98
Figure 24 Floor plan of sampling site A8 99
Figure 25a 24-h representative mean values of PM2.5 in kitchen of sampling site
A8
99
Figure 25b 24-h representative mean values of PM2.5 in living room of sampling
site A8
100
Figure 26 Floor plan of sampling site A9 100
Figure 27a 24-h representative mean values of PM2.5 in kitchen of sampling site
A9
101
Figure 27b 24-h representative mean values of PM2.5 in living room of sampling
site A9
102
Figure 28 Floor plan of sampling site A10 103
Figure 29a 24-h representative mean values of PM2.5 in kitchen of sampling site
A10
103
Figure 29b 24-h representative mean values of PM2.5 in living room of sampling
site A10
104
Figure 30 Floor plan of sampling site B1 109
Figure 31a 24-h representative mean values of PM2.5 in kitchen of sampling site
B1
109
Figure 31b 24-h representative mean values of PM2.5 in living room of sampling
site B1
110
Figure 32 Floor plan of sampling site B2 111
Figure 33a 24-h representative mean values of PM2.5 in kitchen of sampling site
B2
111
Figure 33b 24-h representative mean values of PM2.5 in living room of sampling
site B2
112
Figure 34 Floor plan of sampling site B3 112
Figure 35a 24-h representative mean values of PM2.5 in kitchen of sampling site
B3
113
xiv
Figure 35b 24-h representative mean values of PM2.5 in living room of sampling
site B3
114
Figure 36 Floor plan of sampling site B4 115
Figure 37a 24-h representative mean values of PM2.5 in kitchen of sampling site
B4
115
Figure 37b 24-h representative mean values of PM2.5 in living room of sampling
site B4
116
Figure 38 Floor plan of sampling site B5 117
Figure 39a 24-h representative mean values of PM2.5 in kitchen of sampling site
B5
117
Figure 39b 24-h representative mean values of PM2.5 in living room of sampling
site B5
118
Figure 40 Floor plan of sampling site B6 119
Figure 41a 24-h representative mean values of PM2.5 in kitchen of sampling site
B6
119
Figure 41b 24-h representative mean values of PM2.5 in living room of sampling
site B6
120
Figure 42 Floor plan of sampling site B7 121
Figure 43a 24-h representative mean values of PM2.5 in kitchen of sampling site
B7
121
Figure 43b 24-h representative mean values of PM2.5 in living room of sampling
site B7
122
Figure 44 Floor plan of sampling site B8 123
Figure 45a 24-h representative mean values of PM2.5 in kitchen of sampling site
B8
123
Figure 45b 24-h representative mean values of PM2.5 in living room of sampling
site B8
124
Figure 46 Floor plan of sampling site B9 125
Figure 47a 24-h representative mean values of PM2.5 in kitchen of sampling site
B9
125
Figure 47b 24-h representative mean values of PM2.5 in living room of sampling
site B9
126
Figure 48 Floor plan of sampling site B10 127
Figure 49a 24-h representative mean values of PM2.5 in kitchen of sampling site
B10
127
Figure 49b 24-h representative mean values of PM2.5 in living room of sampling
site B10
128
Figure 50 Floor plan of sampling site C1 133
Figure 51a 24-h representative mean values of PM2.5 in kitchen of sampling site
C1
133
xv
Figure 51b 24-h representative mean values of PM2.5 in living room of sampling
site C1
134
Figure 52 Floor plan of sampling site C2 135
Figure 53a 24-h representative mean values of PM2.5 in kitchen of sampling site
C2
135
Figure 53b 24-h representative mean values of PM2.5 in living room of sampling
site C2
136
Figure 54 Floor plan of sampling site C3 137
Figure 55a 24-h representative mean values of PM2.5 in kitchen of sampling site
C3
137
Figure 55b 24-h representative mean values of PM2.5 in living room of sampling
site C3
138
Figure 56 Floor plan of sampling site C4 139
Figure 57a 24-h representative mean values of PM2.5 in kitchen of sampling site
C4
139
Figure 57b 24-h representative mean values of PM2.5 in living room of sampling
site C4
140
Figure 58 Floor plan of sampling site C5 141
Figure 59a 24-h representative mean values of PM2.5 in kitchen of sampling site
C5
141
Figure 59b 24-h representative mean values of PM2.5 in living room of sampling
site C5
142
Figure 60 Floor plan of sampling site C6 143
Figure 61a 24-h representative mean values of PM2.5 in kitchen of sampling site
C6
143
Figure 61b 24-h representative mean values of PM2.5 in living room of sampling
site C6
144
Figure 62 Floor plan of sampling site C7 145
Figure 63a 24-h representative mean values of PM2.5 in kitchen of sampling site
C7
145
Figure 63b 24-h representative mean values of PM2.5 in living room of sampling
site C7
146
Figure 64 Floor plan of sampling site C8 147
Figure 65a 24-h representative mean values of PM2.5 in kitchen of sampling site
C8
147
Figure 65b 24-h representative mean values of PM2.5 in living room of sampling
site C8
148
Figure 66 Floor plan of sampling site C9 149
Figure 67a 24-h representative mean values of PM2.5 in kitchen of sampling site
C9
149
xvi
Figure 67b 24-h representative mean values of PM2.5 in living room of sampling
site C9
150
Figure 68 Floor plan of sampling site C10 151
Figure 69a 24-h representative mean values of PM2.5 in kitchen of sampling site
C10
151
Figure 69b 24-h representative mean values of PM2.5 in kitchen of sampling site
C10
152
Figure 70 Mean values of PM2.5 observed in the kitchens and living rooms of
the sampling sites
153
Figure 71a Average PM2.5 levels generated from different activities in kitchen
of category-A sampling sites
155
Figure 71b Average PM2.5 levels generated from different activities in kitchen
of category-B sampling sites
155
Figure 71c Average PM2.5 levels generated from different activities in kitchen
of category-C sampling sites
156
Figure 72a Average PM2.5 levels generated from different activities in living
room of category-A sampling sites
156
Figure 72b Average PM2.5 levels generated from different activities in living
room of category-B sampling sites
157
Figure 72c Average PM2.5 levels generated from different activities in living
room of category-C sampling sites
157
Figure 73a Comparison of 24 hour average PM2.5 in houses with kitchens and
living rooms connected
159
Figure 73b Comparison of 24 hour average PM2.5 in houses with kitchens and
living rooms partially connected
159
Figure 73c Comparison of 24 hour average PM2.5 in houses with kitchens and
living rooms not connected
160
Figure 74 Mean levels of PM2.5 obtained during different seasons 161
Figure 75a Maximum and Minimum Air exchange rate in the kitchens of
sampling sites
164
Figure 75b Maximum and Minimum Air exchange rate in the living rooms of
sampling sites
164
Figure 76a Proportion of bacterial species present in the kitchens of the
sampling sites
172
Figure 76b Proportion of bacterial species present in the living rooms of the
sampling sites
172
Figure 77a Proportion of fungal species present in the kitchens of the sampling
sites
173
Figure 77b Proportion of fungal species present in the living rooms of the
sampling sites
173
Chapter One Introduction
1
CHAPTER ONE
INTRODUCTION
Air is an essential component of our lives as it provides us with oxygen to breathe. It
is a medium to sustain life. Air pollution is an issue of major concern for the health since an
increased amount of pollutants emitted into the air means the more amounts of pollutants we
breathe. While there are a variety of sources that pollute the ambient air, the built indoor
environment may also not be as safe as it seems to be. Man has been constructing buildings
since long so as to protect him from the hazards present outdoors such as the harshness of
weather, wild animals etc. Consequently, people in many areas tend to spend 90 % of their
time indoors- either it be at workplaces or at homes (Hoppe and Martinac, 1998). Buildings
can therefore be viewed as an indoor ecosystem or a habitat with varying factors such as the
occupants and their activities, building design affecting the ventilation and air pathways,
material used for construction and the environmental conditions. In fact the interaction of man
with the indoor environment is as complex as the outdoor environment (Goyal and Khare,
2010). Although the indoor air may seem safe from pollutants and other hazards, that is not the
case. As a matter of fact the indoor air may be more polluted than the ambient air. According
to WHO (2002), 2.7 % of the global disease burden can be attributed to indoor air pollution.
The issues of air pollution are not recent ones and date back to prehistoric times when
the cave men started burning fire in their caves. The soot deposited on the walls and ceilings
of these caves provides a sufficient insight into the high levels of pollutants that accumulated
within these dwellings. This points out to the low ventilation present at that time but how much
it must have affected the inhabitants is yet unknown (Spengler and Sexton, 1983). The late
twelfth century saw the use of chimneys in some European houses but it was not until the
Chapter One Introduction
2
sixteenth century that chimney stacks were commonly used. However little attention was paid
to the hazards posed by accumulation of pollutants in the indoor environments (Brimblecombe,
1987; and Burr, 1997). The first related studies were conducted in the 1920’s and 1930’s. Later
on the energy crisis during the 1960’s and early 1970’s boosted the IAQ problems that persist
till date. In order to prevent the outdoor pollutants from entering the indoor environment,
various steps were taken such as insulation of buildings and making then air tight. Although
these steps proved useful in preventing infiltration from the ambient air, it also posed new
problems. The concentration of pollutants indoors was found to be higher than the outdoor
levels. There are a variety of sources in the indoor environment indoors which may lead to a
higher pollutant level than the ambient air (D’Amato et al., 1994; and Teichman, 1995). It is
therefore necessary to study these sources also in order to ensure a healthy indoor environment.
Indoor air quality is closely defined by the outdoor air quality. However there are a variety of
factors in the indoor environment whose interaction can strongly determine the IAQ. These
factors include:
The movement of occupants resulting in re-suspension of already deposited dust and
contaminants
Activities of the occupants thereby generating varying amounts of pollutants
Sources and sinks of pollutants, and
The movement of air within the different parts of the building and from the outdoors
affecting the removal as well as dispersion of pollutants
There are a variety of sources for the indoor pollutants that can contribute to indoor air
quality (IAQ) as summarized in table 1 below (Source: Jhang and Smith, 2003). These sources
Chapter One Introduction
3
vary in nature such as external, internal, biological or chemical sources (Goyal and Khare,
2010).
Table 1: Indoor air pollutants and their sources
Pollutant Major indoor sources
Particulate Matter (PM) Combustion such as fuel burning, second hand smoke,
cleaning, cooking
Carbon monoxide (CO) Combustion such as fuel burning, second hand smoke
Nitrogen oxides (NOx) Combustion such as fuel burning, second hand smoke
Sulphur oxides (SOx),
Arsenic and Fluorine Burning of coal
VOC’s
Combustion such as fuel burning, second hand smoke,
paints, cleaning solvents, furnishing, cooking activities,
materials used for construction
Aldehydes Furnishing, cooking activities, materials used for
construction
Pesticides Cleaning solvents, outdoor sources such as dust from
outside
Asbestos Renovation and/or demolition of construction materials
Lead Remodeling and/or demolition of painted surfaces
Biological pollutants such dust
mites, pollen, animal dander,
air-borne bacteria and fungi
Moist or water-damaged walls, floors, ceilings, carpets,
bedding and from poorly maintained HVAC systems
Radon Soil and construction materials
Apart from these sources, “sinks” also play an important role in defining the IAQ.
“Sinks” are high surface area sites which may be porous in nature. Odours and other gaseous
pollutants can deposit on these surfaces which eventually turn into secondary sources for these
pollutants. In addition to deposition, sinks can include dispersion processes as well as chemical
reactions. Air movement is also an integral part of the IAQ. Air movement in a building may
be natural or forced by a HVAC system. Similarly the ventilation system is responsible for the
infiltration and ex-filtration of air in and out of the building. As a result the pollutants can move
Chapter One Introduction
4
in and out of the indoor micro-environments. The flow of pollutants in the indoor environment
is summarized in figure 1.
Figure 1: Flow of pollutants in an indoor environment
INDOOR LIVING ENVIRONMENT
The indoor living environment is integral to humans as in most cases, people tend to
spend more than 90% of time indoors. There are a number of factors that characterise the built
environments and play a substantial role in defining the air quality. There is a complex
relationship between the indoor environment and the wellbeing of the occupants (Bluyssen et
al., 2013). The presence of a multitude of stressor in the indoor environment such as moisture,
mold, noise, light, thermal comfort or discomfort, particulate can significantly affect the life
of people. The synergistic effect of these stressors can produce short term and long term effects
on the human health such as the sick building syndrome (Bluyssen, 2009).
Pollutants enter the house through infiltration
Indoor sources (such as building material, occupant's activities, furnishing, consumer products)
also contribute towards pollutant loads
Are removed or diluted by ventilation
Re-enter the building
Within the building, the pollutants
Are inhaled by the occupants
Are exhaled by the occupants
Chapter One Introduction
5
The life style of people generally describes the IAQ and Bluyssen et al. (2011) has
given a checklist to identify the various descriptors in a built environment which include the
following components:
1. Characteristics of the built environment: building location and surroundings
2. Characteristics of building, systems and rooms: building material, furnishing, HVAC
system, lighting system etc.
3. Maintenance and operation of the building and activities: cleaning, renovation,
maintenance of HVAC system etc.
Among the psychosocial environments the living environment includes sub-
components such as number of people, social background etc. These descriptors have been
found to be useful in studying the well-being of an individual in association with the built
environment.
The research undertaken explored two major micro-environments of residential
buildings i.e. kitchens and living rooms. Their air quality was assessed and the presence of
environmental stressors was also investigated via direct questioning. Although the indoor air
hosts a multitude of pollutants, the present study is concerned with concentration of fine
particulate matter and bio-aerosols in the indoor air of residential buildings and so we limit our
focus to these two major indoor pollutants.
PARTICULATE MATTER
Particulate matter (PM) is one of the six criterion air pollutants and the most harmful
one (Pope and Dockery, 2006). Particles are generated into the atmosphere through a variety
of sources and may be natural or anthropogenic; primary or secondary in their origin.
Chapter One Introduction
6
Particulate matter includes a variety of chemical and physical pollutants dispersed in the air
and are generally defined as complex mixtures of solid and liquid particles from organic and
inorganic sources in the air (Tiwary and Colls, 2010; and WHO, 2011). Particulate matter is
categorized broadly into:
Suspended particulate matter (SPM)
Respirable particulate matter (RSPM)
The total suspended particulate matter includes refers to larger particles with no specific
size limit and the upper limit is dependent upon wind speed and the sampler orientation. The
respirable PM includes particles with an aerodynamic diameter of 10 µm and below as defined
by the USEPA while the American Conference of Government Industrial Hygienists (ACGIH)
considers the respirable PM to be having an aerodynamic diameter of 2 or less than 2 µm in
size (Goyal and Khare, 2010; Parsia et al., 2010; and Tiwary and Colls, 2010). The
aerodynamic diameter of a particle is defined as follows:
“The aerodynamic diameter of any particle is the diameter of a sphere of unit density (water
density) that would have the same settling rate in still air as the actual particle.”
Particulate matter is defined on the basis of the size or diameter of the particles since it
is a determinant of many properties of the particles such as residence time in the air, distance
travelled before deposition, and deposition in the respiratory system. The deposition efficiency
of various particles in the respiratory system is an important factor since it enables us to
understand the risk we stand at. The most commonly studied PM fractions include particulate
matter with an aerodynamic diameter of 10 µm (PM10) and below. PM10 and PM2.5 are of
greater significance in air quality policies and regulations for particle emissions since they are
Chapter One Introduction
7
easily inhaled and affect the human health (Wiseman and Zereini, 2010). The particulate matter
can be classified according to their deposition in the respiratory tract as given in figure 2:
Figure 2: Categories of particulate matter according to size
Particulate matter enters the human body through inhalation. After inhalation, there are
three possibilities (Gentry, 2005):
The particles may be removed through exhalation before they deposit even in the nasal
passage
They deposit in the body and reach deeper in the lungs, or
After deposition, they may be removed by mucociliary transport
Once inside the nasal passage they tend to deposit in the respiratory tract depending on
their aerodynamic diameter, the speed with which air is being inhaled and the residence time.
Larger particles tend to settle by gravity and have higher impaction efficiencies in high
airspeeds while the smaller particles employ sedimentation in addition to the Brownian
diffusion velocities in low airspeeds and longer residence times. Apart from these primary
mechanisms of particles deposition (settling by gravity, Impaction and Brownian diffusion),
there are two secondary mechanisms involved as well namely electrostatic attraction and
INHALABLE < 50 µm
THORACIC < 10 µm ALVEOLAR < 4 µm
Chapter One Introduction
8
interception. However these secondary processes are of least significance as major role is
played by the primary mechanisms.
There is a direct relation between the particle size and their settling rate in the
respiratory tract (Fierro, 2000) and the construction of the human respiratory system is
responsible for the way in which particles of varying size deposit in different regions of the
tract. The particles inhaled by us are less than 100 μm in size among whom those with a size
of above 50 μm are deposited immediately at the start of nasal passage before entering the
trachea. Particles with an aerodynamic diameter greater than 10 μm deposit on hair in the nasal
passage, and on the walls of nose and throat through inertial impaction while the particles
having a size of 2 or less than 2 µm tend to deposit in the lower respiratory tract. These particles
reach the alveolar region and can interfere with the gas exchange. Larger particles (size ranging
from 2 to 5 µm) deposit in the conducting air ways of lungs while particles with a size between
5 to 10 µm are trapped in the upper respiratory tract with few particles reaching the lower
respiratory tract. Particles larger than 10 µm are easily removable as they do not reach further
than the nasopharyngeal region and can be removed during coughing and/or sneezing (figure
3).
Chapter One Introduction
9
Figure 3: Deposition of particulate matter in the various regions of respiratory tract according
to their size
The balance between the deposition modes of particles is influenced significantly by
the breathing rate. During the resting phase, airspeed is low with the result that not much
settling or diffusion of particles can occur. On the other hand, during heavy exercise, the total
volume of the air entering the lungs through nose is increased. Moreover oral breathing also
contributes a significant volume of air to the lungs. Consequently the penetration of coarse
particles is increased since the nose is unable to filter the particles inhaled through the mouth
(Tiwari and Colls, 2010).
Apart from the mechanism of lung clearance through coughing (mucociliary system),
there is another process i.e. phagocytosis at work that is responsible for protection of the
respiratory system and the human body on the whole from harmful foreign objects that we
Chapter One Introduction
10
inhale daily. The smaller particles including not only the particulate matter but also the bio-
aerosols can penetrate deeper into the alveoli and diffuse easily through the thin walled blood
capillaries. However the macrophages (type of white blood cells found in the alveoli) typically
engulf the micro-organisms and the PM that attempts to enter the blood stream in the alveolar
capillaries. As a result, these two mechanisms provide a natural defense against the inhaled
particles provided they do not exceed the normal limits (Kowalski, 2006).
FINE PARTICULATE MATTER (PM2.5)
COMPOSITION & SOURCES
Fine particulate matter refers to the suspended particles with an aerodynamic diameter
of 2.5µm or less and their origin and chemical composition differs greatly from PM10. Fine
particles are obtained by the combustion of oil, coal, gasoline, diesel and wood, Gas to particles
conversions. They are formed by a number of processes such as chemical reactions,
condensation, nucleation, coagulation, cloud and fog processing. They are hygroscopic in
nature and consist of sulphates, nitrates, ammonium, elemental carbon, organic compounds,
water and metals such as lead (Pb), Cadmium, (Cd), Vanadium (V), Nickel (Ni), Copper (Cu),
Zinc (Zn), Manganese, (Mn), and Iron (F). Being smaller in size, existence of fine particles
extends from days to weeks and they travel from hundreds to thousands of kilometers away
from their point of origin (Fierro, 2000). Fine particles have high surface area and the ability
to absorb a number of organic compounds which may be more harmful to human health (Bates,
1995).
Fine particulate matter is generated from a variety of sources as mentioned earlier. Both
the indoor and outdoor environments are associated with aerosol generation. However the
identification of these sources as well as their contribution toward air quality is a relatively
Chapter One Introduction
11
complicated process. The source and source strength contributing towards the pollutant level
should be identified in order to have a clear understanding of the source and sink of the
particles. Particulate matter may have a direct and/or indirect (secondary) source. Although
particulate matter is generated from a variety of natural and man-made sources in the ambient
air, the indoor air is mostly described by anthropogenic sources. Some of these sources include
heating, cooking, cleaning, walking around, smoking cigarettes, paints, etc. and also the
building material and furnishing (Ferro et al., 2004; Mitchell et al., 2007). The composition of
PM is also as variable as the sources it comes from. The major components in both indoor and
outdoor PM have been identified to be water along with NaCl, sulfates, nitrates, ammonia,
carbon, and mineral dust (WHO, 2011). The seasons and region under study influence the
composition of the particulate matter. Many studies have been carried out to observe the
components of particulate matter so as to have a deeper understanding of the pollutants we
inhale and the risk they present to us. In a study in USA, 79-85% of the fine particulate matter
was observed to be composed of ammonium, organic carbon, elemental carbon, nitrate,
sulfates, and sodium (Parsia et al., 2010). Apart from these, transition metals, ions such as
those of sulphates and nitrates, minerals, reactive gases, and particles having a biological origin
also constitute the PM2.5 fraction. The presence of these components may be from local and in
some cases, regional sources as well.
HEALTH IMPACTS OF PM2.5
According to the International Agency for Research on Cancer (2013), outdoor air
pollution is a leading cause of lung cancer. In the developing countries, indoor air pollution is
the cause of approximately 2 million premature deaths. Pneumonia causes approximately half
of these deaths in children below 5 years of age. Among the major air pollutants, particulate
Chapter One Introduction
12
matter is known to affect more people than other pollutants. Moreover, inhalation of PM2.5 is
estimated to be the cause of about 2.4 million premature deaths per year according to WHO
figures (Tiwari and Colls, 2010). More recently, WHO reports the number of premature deaths
due to household air pollution (HAP) in 2012 to be approximately 4 million which makes about
7.7% of the global mortality (Bruce et al., 2015).
According to Brauer et al. (2012), 99% of people in South and East Asia reside in areas
with poor air quality where PM2.5 levels greatly exceed the WHO limits of 25 µg/m³. Daily
exposure to particulate matter causes an increase in the deaths due to respiratory and
cardiopulmonary diseases (Samet et al., 2000; US-EPA, 2003). Adults are more vulnerable to
pneumonia, asthma, chronic obstructive pulmonary disease (COPD), cough, phlegm and other
respiratory diseases along with the cardiac cases as compared to children (Kappos et al., 2004).
Lung cancer, cardiovascular and respiratory problems are a result of long term exposure to
PM. The situation is worse in developing countries where biomass fuel is still in use in rural
areas which can lead to wheezing, exacerbation of asthma, chronic bronchitis, respiratory
infections, Acute Lower Respiratory Infections (ALRI), Chronic Obstructive Pulmonary
Disease (COPD) and also lung cancer (Bruce et al., 2002). Prolonged exposure can lead to
increased mortality resulting from cardiovascular diseases as well. This excessive exposure
can cause acute bronchial irritation, inflammation and increased reactivity. As a result there is
reduced mucociliary clearance and reduced macrophage response towards foreign elements,
thereby reducing local immunity. This PM induced pulmonary inflammation can also cause
oxidative stress and affect the cardiovascular system by triggering the production of
procoagulant factors in the lungs. The inflammatory mediators may also promote myocardial
Chapter One Introduction
13
infarction by acting to increase the levels of procoagulants in the lungs (Fierro, 2000; Bruce et
al., 2002).
In order to measure the health effects related to aerosols, a physical parameter called
dose is employed. It depends upon the amount of particles in the body. However since it is not
possible to measure the dose of inhaled aerosols directly, measurement of the size distribution
of particles in the breathing zone and aerosol deposition, knowledge of the relevant parameters
such as temperature and humidity in the respiratory tract, and a knowledge of the biochemical
processes (translocation, clearance, and absorption) within the lungs is required for reliable
dose determination (Ruzer et al., 2005).
BIO-AEROSOLS
Micro-organisms are present everywhere – in the air, soil, water, plants, human body.
These include bacteria, viruses, fungi, spores, mites, and pollen. Among these, the air borne
micro-organisms and their related products such as their cellular components are termed as
biological aerosols or bio-aerosols. These may be viable (alive) or non-viable (dead) and are
responsible for a variety of health related problems. These microbial particulate matters are
found in both the indoor and the outdoor environment. The sources and sinks of bio-aerosols
vary in different environments. Carpets in an indoor environment can trap these particulates
very easily and firmly and also provide a suitable environment for their survival and re-
distribution into the air (Hospodsky et al., 2012). Similarly water damaged places also provide
the necessary environmental conditions required for the survival and growth of bacteria and
fungi. Most fungi present in the indoor air have their sources in the ambient environments
while in case of bacteria indoor as well as outdoor sources are responsible. The sources of bio-
aerosols may be living such as humans, plants, and pet animals or non-living materials such as
Chapter One Introduction
14
building material, damp indoor spaces and many others. Also the bacteria and fungi growing
in damp indoor spaces have a different profile from those generated from human sources
(Damp Indoor Spaces and Health, 2004; Hospodsky et al., 2012; Prussin and Mar, 2015).
The levels of the biological contaminants in the indoor micro-environments are under
the influence of some factors. Among these time of the day, time of the year and also the
geographic location of the concerned place are the most notable. Apart from these, some other
physical parameters are also important such as climate and weather conditions, temperature of
surrounding air, temperature of the depositing surfaces, relative humidity (RH), wind speed,
and turbulence in the air. The external conditions are different for each species and thus are
their responses. The air temperature, surface temperature, relative humidity, and changes in
wind speed are determinants of the variations in bio-aerosols levels as well as different species
composition of the air during the day and night. Similarly the two most important physical
parameters influencing the microbial activity are temperature and RH and are responsible for
the changes in species composition during the shifting seasons. It has been documented that
during the summer season, culturable bacterial and fungal spores are present in higher numbers
than in during winters due to the dry conditions. The location of the study area is also an
important factor since in urban areas higher bioaerosols loads are present in the air than in the
rural areas (Heikkinen et al., 2005).
Human beings are exposed to bio-aerosols through inhaling; the most efficient route of
transmission of infectious agents (Evans, 2000). However it is important to note that not all
the air-borne microbes we inhale are harmful for health. In fact most of them are harmless with
only a small proportion of bio-aerosols being unhealthy (Heikkinen et al., 2005). Exposure to
Chapter One Introduction
15
these bioaerosols can cause a variety of diseases which are generally classified under three
categories with the first two being more common (Douwes et al., 2003):
Infectious diseases
Respiratory diseases
Cancer
The response of the human body towards bio-aerosols may result in acute or chronic
health issues. The following table summarizes some of these conditions (Heikkinen et al.,
2005; Walser et al., 2015).
Table 2: Health effects of exposure to bio-aerosols
Acute Chronic
Rhinosinusitis Asthma
Influenza Bronchitis
Pharyngitis Some Pulmonary Infections
Significant decrease in forced vital
capacity of lungs (FVC)
Significant decrease in lung function
parameters
Upper Airway Obstruction
Bronchitis
Alveolitis
Pulmonary Edema
Laryngitis
Bacteria are a diverse group of micro-organisms. They vary in size from 0.2 to 5.0 μm
and in shape from spherical to elongate. They are responsible for a variety of diseases in not
only humans but also animals and even plants. Bacteria may be sporulating or non-sporulating,
existing as individual cells or in groups. Many sporulating bacteria are actinomycetes
(sporoactinomycetes) and are responsible for respiratory infections. These bacterial species
tend to show a similarity in behaviour with fungal spores growing like mycelia in the presence
Chapter One Introduction
16
of suitable moisture content and other nutrients. Bacteria originating from human sources
generally include gram-positive Cocci such as Staphylococci spp. and Bacillus spp., while
some other typical bacterial species present in the ambient air include Bacillus anthracis,
Clostridium botulinum, Clostridium perfringens, Corynebacterium, Flavobacterium,
Micrococcus, Pseudomonas, Streptomyces, and other sporoactinomycetes (Damp Indoor
Spaces and Health, 2004; and Kowalski, 2006).
On the other hand, the aerodynamic diameter of most fungal spores is between 2 to 10
µm which tend to readily settle on indoor surfaces due to gravity. They may vary in shape from
round to barrel shaped. Cladosporium, Aspergillus, Penicillium, Alternaria, Fusarium,
Saccharomyces, Trichoderma, Neurospora, Epicoccum, and many other species are most
commonly found in the indoor as well as outdoor air (Mullins, 2001). Fungal spores colonize
frequently in the indoor damp spaces where their levels can exceed those of the ambient air.
These spores have been reported to be responsible for allergic reactions, respiratory infections,
and other related problems (Kowalski, 2006).
IMPACT OF VENTILATION ON INDOOR AIR QUALITY
A constant supply of fresh air in the indoor micro-environments is an important factor
to maintain a healthy environment. Ventilation practices vary around the globe with natural
and/or mechanical sources in use. Ventilation is defined as the supply of sufficient amounts of
fresh air in the indoor air so that the occupants are able to breathe easily and the pollutants
accumulated or generated from indoor sources can be diluted and removed by the influx of air
in and out of the building. A higher rate of ventilation means smaller residence time of the
pollutants indoors. Ventilation may be natural, mechanical (fans and/or HVAC systems) and
hybrid also (using both modes). However while the pollutants are diluted by the influx of
Chapter One Introduction
17
ambient air towards indoors, the case can also be opposite when the outside environment is
more polluted causing more pollutants to flow inwards. The HVAC systems can harbor a
variety of micro-organisms which pose a health risk. Still the HVAC systems, if properly
maintained, can be useful in maintaining a good IAQ. Natural ventilation is inexpensive as
compared to mechanical ventilation but it is also uncontrolled as the airflow is unpredictable
under changing climate. Moreover the opening and closing of windows and any other such
opening also affects the infiltration of outdoor air (Awbi, 1991; Allard, 2002).
The location, shape and size of the building along with the wind direction and
topography are some of the numerous factors that affect air flow in naturally ventilated
buildings. The temperature and relative humidity of both the indoor and outdoor air is also
important. The thermal buoyancy and wind pressure are the two driving forces that cause
thermal and pressure gradients in the air causing the airflow from outside to inside environment
(ASHRAE, 1989 and 2001).
The methods employed for measurement of ventilation rates inside a building take into
account either the number of people in a given area (liters/second/person) or use the volume
of the building (air change rate per hour, ACH) (Fischer-Mackey, 2010). For this purpose tracer
gases such as CO2, SF6, and C6F6 are employed. The most commonly used gas is carbon
dioxide due to being readily available and also for being cheap. Three methods are generally
in use namely; constant injection method, concentration decay method and the constant
concentration method (Laussmann and Helm, 2011). The concentration decay method has been
employed in this research work.
Chapter One Introduction
18
CONTROLLING AIR POLLUTION
Indoor air pollution is an important issue which needs to be tackled properly. The first
very necessary step in this regard is the identification of the source. US-EPA lays emphasis on
the removal of pollutant source as the most effective strategy in pollution control. Similarly
effective use of adequate ventilation is also a preferred in case of unidentified source, costly
source treatment and/or localized source (Goyal and Khare, 2010). Generally the following
methods are suggested to control air pollution in the indoor environments.
Removal and/or substitution of the pollutant source
Filtration of the pollutants
Dilution of the indoor air with the help of ventilation
Isolation of the source (encapsulation)
Time specific use of the contaminat source if required
Educating the occupants about the IAQ issues
INDOOR AIR QUALITY IN PAKISTAN
Indoor air quality is an issue of prime importance particularly in the developing
countries where biomass fuel is still burnt in rural areas. The status of air quality in the urban
centres is also pitiable as lack of knowledge leads to not realizing the health hazards related to
inhaling polluted air. Like many developing countries, Pakistan also faces serious pollution
issues. The Pakistan Environment Protection Agency (Pak-EPA) has conducted numerous
studies to record ambient levels of particulate matter in various urban centers of the country
with many other related researches at institutional/university level as well (Pak-EPA, 2001,
2002, 2003; Hashmi and Khani, 2003; PEP, 2006, 2007; Ghauri et al., 2007; Lodhi et al., 2009;
Mansha et al., 2012; Zainab et al., 2015; and Zona et al., 2015). The government has setup
Chapter One Introduction
19
NEQS for setting a limit for the amount of a particular pollutant to be present in the ambient
air. However sadly enough, indoor air pollution still requires to be recognized as a potential
health hazard at policy level. There is no guideline available for setting the limits for
concentrations of pollutants in the indoor environments. With the exception of some studies
there is no detailed data regarding the monitoring of concentrations of fine particulate matter
or air-borne bacteria and fungi in the residential built micro-environments (Akhtar et al., 2007;
Colbeck et al., 2008, 2010; Siddiqui et al., 2005a, 2005b, 2008, 2009; Nafees et al., 2011;
Janjua et al., 2012; Nasir et al., 2013, 2015; Sidra et al., 2015; Amanat et al., 2015; Ali et al.,
2015a; Saeed et al., 2015; Abbas et al., 2015). Moreover, most of these studies focus on PM
generation from biomass fuel burning and the subsequent health impacts on the exposed
population and the IAQ of the urban areas have not been extensively explored yet.
In many developing countries, including Pakistan, indoor air pollution annually claims
1.2 million lives as reported by WHO (2007). In Pakistan, it is a significant burden on the
economy and costs 1% of the GDP. The World Bank reported an annual figure of 28,000 deaths
with 40 million reported cases of acute respiratory illness in Pakistan (World Bank, 2006).
According to recent figures, these PM2.5 levels are the cause of more than 9,000 premature
deaths per annum which represent 20% of acute lower respiratory infection (ALRI) mortality
among children under five years of age, 24% of cardiopulmonary mortality, and 41% of lung
cancer mortality among adults 30 or more years of age in the major cities of Pakistan. About
12% of the deaths occur in children below five years of age and 88% are among adults. Almost
80% of the death losses are in Karachi. Particulate matter is also estimated to cause 59% cases
of chronic bronchitis in these cities, over 1.6 million cases of ALRI in children, more than 100
million restricted activity days, and over 300 million respiratory symptoms annually. These
Chapter One Introduction
20
annual health effects represent 203,000 DALYs, of which 97,000 are from premature mortality
and 106,000 from morbidity (Sánchez-Triana et al., 2014).
Pakistan is one of the world’s highly populated countries (ranking 6th among other
countries) comprising of 2.62% of the world’s population (179 million people estimated in
2012) (United Nations Department of Economic and Social Affairs, 2012). With an increasing
trend in population dynamics, Pakistan Economic Survey (2009 – 2010) estimates the
household size to be 7.2 persons on average. With 64% of its population residing in rural areas,
Pakistan is a predominantly rural community where use of biomass fuels is widespread owing
to its easy availability and low cost. It is estimated that 90% of rural households employ solid
fuels for cooking and other purposes such as space heating etc. while 22% of urban households
also use solid fuels for cooking (Sheraz and Zahir, 2008). However, little are the people aware
of the hazards they are exposed to and at what cost. Nasir et al. (2015a) explored the socio-
economic conditions of Pakistan which play an integral role in fuel selection and highlighted
poverty as the major factor. Colbeck et al. (2010) reviewed the status of indoor air quality in
Pakistan and highlighted the various factors resulting in poor health condition of indoor
environments. Despite the worse conditions of the indoor environments particularly in rural
areas, policy makers are still ignorant of the hazards to which majority of the population is
exposed to. It is a much needed step to recognize indoor air pollution at policy level so that
mitigation measures can be initiated.
Owing to the limited number of studies regarding monitoring of air quality in Pakistan,
we are unable to determine the exposure level of general public towards environmental
pollutants. As mentioned earlier, majority of the studies conducted were concerned with PM
levels in rural settings where biomass fuel burning is a common practice. Urban centres have
Chapter One Introduction
21
been ignored largely in these studies. Keeping in mind these facts, the current study was
designed to monitor the levels of fine particulate matter and air-borne microflora in a random
assortment of residential houses of Lahore, Pakistan to gain an insight into the air quality of
these houses and to assess the risk associated with exposures to indoor contaminants for the
occupants.
Chapter One Introduction
22
AIMS AND OBJECTIVES OF THE STUDY
As concluded in the above chapter, there is a poor record of indoor air quality in
Pakistan. Consequently, the current study was designed keeping in view the lack of data on
indoor air quality in urban areas of Pakistan. The underlying purpose of this research work was
to determine the state of air quality in the residential micro-environments of urban areas and
to identify the sources responsible for higher levels of particulate matter and micro-organisms
in the indoor environment. It was also perceived to study the relation of various factors
responsible for defining the indoor air quality of residential areas and the exposure risks to the
residents so that reasonable measures may be proposed to overcome the hazards posed by
particulate pollution and bioaerosols.
Based on these aims, the following objectives were defined for this study:
1. Real-time monitoring of mass concentrations of PM2.5 in the kitchens and living rooms
of different houses in Lahore
2. Qualitative assessment of bio-aerosols in kitchens and living rooms of these houses
using settle plates
3. Correlation of particulate matter concentration indoors with different urban
congestions
4. Seasonal variation of fine particulate matter and air-borne bio-aerosols in different
urban residential micro-environments
5. Recommendation for a standard value of permissible levels of PM2.5 concentrations
indoors in Pakistan
Chapter Two Literature Review
23
CHAPTER TWO
LITERATURE REVIEW
Particulate matter is ubiquitous in the environment with a wide variety of sources and
sinks present in the nature apart from the human induced factors. Air quality is an issue of
immense importance owing to the disease burden related to exposure to particulate matter and
subsequent increase in mortality rates all over the world. The indoor environment harbours a
different range of sources than the outdoor environment and many studies have identified and
documented the sources and their emission rates for particulate matter. Although there are a
number of studies regarding indoor air quality in many developed and developing countries,
Pakistan faces a scarcity of data in this context as discussed in the coming paras.
INSTRUMENTS FOR PARTICULATE SAMPLING
There are a number of techniques applied for particulate sampling. The two most
widely used methods for aerosol monitoring are the gravimetric method and the light-scattering
method. Niu et al. (2002) reviewed the efficiencies of these two methods and found out that
gravimetric method is more suitable for use as a reference while the light-scattering
instrumentation should be used for preliminary measurements. The current research work
employed DustTrak aerosol monitor (TSI, Inc. Model 8520) which is a light scattering
instrument for real-time monitoring of indoor PM2.5 levels. As the following comparative
studies concluded, DustTrak gives more precise results when dealing with smaller particle size.
In a study by Yanosky et al. (2002) two direct reading aerosol monitors were collocated
indoors to compare their efficiency. The Aerodynamic Particle Sizer (APS) (TSI, Inc. Model
3320) and DustTrak Aerosol Monitor (DustTrak) (TSI, Inc. Model 8520) were used in this
study and 24-h samples were collected. Paired-t test and regression analysis were applied on
Chapter Two Literature Review
24
the data thus obtained. It was found out that DustTrak gave more precise and accurate
measurements of PM2.5 which were in accordance with a US EPA designated Federal
Reference Method (FRM) PM2.5 sampler, the BGI, Inc. PQ200.
In another similar study by Cheng (2008), DustTrak (TSI Model 8520) and Grimm
Series 1.108 Aerosol Spectrometer were used to measure PM2.5 and PM10 within an iron
foundry. These both are direct reading, real-time aerosol monitors. For comparison of these
two instruments and as a reference gravimetric method the SA Model 241 Dichotomous
Sampler was used. During the study it was found that DustTrak gives more precise results
when particle size decreases.
SOURCES OF PARTICULATE MATTER IN THE INDOOR ENVIRONMENT
There is a wide variety of sources for particulate matter in both the indoor and ambient
air. However, particulate matter is not only generated by the indoor or outdoor sources; the
existing PM can also cause fluctuations in monitored PM levels owing to their deposition rate
and their subsequent re-suspension. Thatcher and Layton (1995) studied the deposition,
penetration and re-suspension of particulate matter in a house in California. The same spot was
selected for studying the three processes. For measuring the deposition rate, the particle
concentration was raised and simultaneously the air infiltration rates were measured. For
particle size ranging from 1-5 µm in diameter, the deposition velocity closely matched the
calculated settling velocity while it was less for particles larger than 5 µm, most probably due
to the non-spherical nature of these particles. The penetration factor was found to be 1 which
was indicative of the non-effectiveness of the building shell in removal of infiltrating particles.
Similarly re-suspension of dust was measured under different conditions and was observed to
be increased up to 100% by walking alone. Presence of four people in the house involved in
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25
minor activities generated a re-suspension rate ranging between 1.8 x 105 and 3.8 x 104/hour
for super micron particles.
Recently, Zhou et al. (2011) studied the re-suspension of dust particles deposited in
ventilation ducts. A physical science based model was developed and it was found out that re-
suspension of these previously deposited particles was an important contributor to higher levels
of particulates indoors. While fresh air had little influence on exposure rate, increased
ventilation rate lead to an increase in exposure to this re-suspended dust.
Although the deposition and resuspension of particulate matter are important sources,
the activities carried out in the indoors are also influencing factors. Several studies have been
conducted to confirm the sources and source strengths of everyday activities in relation to
particulate matter.
Monn et al. (1997) investigated the relationship between indoor and outdoor
concentrations of PM10, PM2.5 and NO2 in seventeen different households. Smoking was found
to have the most profound effect on I/O ratios i.e. > 1.8. Houses with no apparent sources had
an I/O ratio of 0.7. Human activities contributed a lot to particulate matter even in those houses
with little or no apparent indoor sources. Gas cooking contributed to higher levels of NO2 in
some homes i.e. > 1.2 while in other homes the I/O ratio was found to be less than 1.
Chao et al. in 1998 observed that a high Respirable Suspended Particles (RSP) to Total
Suspended Particles (TSP) ratio was found indoors. Levels of particulate matter indoors
increased during cooking, smoking and burning of incense. However, in case of heavy rain and
high ventilation rate indoor particulate level fell by 20%.
The source strength of various activities was determined by Abt et al. (2000) in four
houses in Boston as an extension of a previous investigation. A physical model was used to
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study the source strengths and also the ventilation rates affecting the particulate matter levels
of varying sizes. PM fractions having a size ranging between 0.7 to 10 μm were generated from
activities such as cooking, cleaning and movement of people around the house while cooking
also contributed a significant proportion of particles with a diameter below 0.5 μm. Outdoor
sources were also a contributing factor towards indoor particulate levels. Gravitational settling
caused an increase in the deposition efficiency of larger particles which were thus easily and
readily removed from the surrounding air.
Mass concentrations of PM10, PM2.5 and PM1 were measured inside and outside of
seven urban and two rural houses in UK for a period of twelve months. The study revealed that
the major source of particulates indoors was from outdoors. An activity chart was filled by the
occupants to determine which activity contributed more to particulate matter indoors. Cooking,
cleaning, smoking and general activities contributed highly to PM10 concentrations indoors
while cooking and smoking contributed to PM2.5 and PM1 more than cleaning and other
activities (Jones et al., 2000).
Air samples were analyzed from eight different homes of Hong Kong for source
appointment (Chao and Cheng, 2002). Five sources were identified such as smoking, cooking,
burning incense, human activities indoors, and outdoor sources. The major source of PM2.5 was
identified to be cooking with an average of 61.9% of the total PM2.5 concentrations indoors.
Outdoor sources provided for most of the PM10 concentrations (49.3%) with human activities
on second place (29.9%).
Concentration of particulate matter indoors and outdoors was measured in 34 homes of
Hong Kong. It was found that since windows remained closed during most time of the day due
to fall and winter season, a poor correlation existed between the indoor and outdoor
Chapter Two Literature Review
27
concentrations. The mean indoor PM2.5 and PM10 concentrations were found to be 45.0 and
63.3 μg/m3, respectively while the corresponding mean outdoor levels were 47.0 and 69.5
μg/m3, respectively. Moreover the use of window type air conditioners contributed to low air
change rate (Chao and Wong, 2002).
Riley et al. in 2002 applied a model to study the level of indoor particulate matter due
to sources from outdoors which included the distribution of ambient particles on the basis of
their size, type of building and operational parameters. It was concluded that in order to
determine the exposure to particulates of outdoor origin, the efficiency of removal processes
in different buildings according to size must be considered.
PM2.5 and PM1 were measured in ten homes of urban area of Taipei in winter and
summer season by Li and Lin, (2003). The average concentration of indoor PM1 was measured
to be 25.88 μg /m3 while the outdoor concentration was 25.86 μg /m3. On the other hand the
mean indoor and outdoor concentration for PM2.5 was 37.60 and 37.26 μg /m3 respectively.
Moreover no significant difference was found in the mean concentration of both PM2.5 and
PM1 for the winter and summer seasons. For PM1, the average summer and winter levels were
found to be 25.13 μg /m3 and 26.70 μg /m3 while for PM2.5 their respective levels were
measured to be 36.45 μg /m3 and 38.51 μg /m3.
PM2.5 daily concentrations and 15-min average was measured in three residential areas
of St. Paul (Ramachandran et al., 2003). 9-10 houses were selected from each locality for
indoor measurements while the outdoor monitoring was conducted at a central monitoring site
at each locality. While the outdoor concentrations did not vary greatly, a varying trend in
indoor concentration was noted. Measurements were made in the summer, winter and autumn
of 1999 and a strong seasonal effect on 15-min average PM2.5 concentration was observed. The
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values were higher in the spring and summer than in fall since the windows were kept open
more often during spring and summer season.
A mathematical model was applied by Ferro et al. (2004) to provide an estimation of
the source strength of various household activities. Different everyday activities such as
folding blankets and clothes, walking around, dancing, sitting on furniture and many more are
responsible for re-suspension of dust particles, forming a “personal dust cloud”. Source
strength for PM2.5 was found to range between 0.03 to 0.5 mg min-1 while that for PM5 was
from 0.1 to 1.4 mg min-1. The source strengths were found to be a function of the number of
persons performing the activity, the vigor of the activity, the type of activity, and the type of
flooring.
Ambient particles are considered to be an important source of particulate matter found
indoors. Hänninen et al. (2004) studied the infiltration of ambient particles into indoor
environments in four European countries. The mean concentration of ambient particles in
indoor air ranged from 7μg/m3 in Helsinki to 21μg/m3 in Athens. However a significant portion
of indoor air could not be explained.
Concentration of elemental carbon and organic carbon present in PM2.5 air sample was
analyzed in a study by Ho et al. (2004). Five roadside buildings i.e. three residencies with
natural ventilation and two buildings (a class room and an office) with mechanical ventilation
were selected for the study. The outdoor concentration of PM2.5 was found to be 78.4 μg/m3
with organic carbon concentration to be 12.6 μg/m3 and elemental carbon concentration to be
6.4 μg/m3. On the other hand the indoor PM2.5 concentration was measured to be 55.4 μg/m3
while the OC and EC concentrations were 11.3 and 4.8 μg/m3. The major source of indoor
PM2.5, elemental carbon and organic carbon was observed to be the penetration of outdoor air.
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Koistinen et al. (2004) investigated the source contributions to the mass concentrations
of PM2.5 in personal exposures and in indoor and outdoor residential microenvironments, and
also in workplace indoor microenvironments of nonsmoking adult population unexposed to
environmental tobacco smoke in Helsinki, Finland. The major sources were identified to be
inorganic secondary particles, primary combustion, and soil in all the microenvironments and
personal exposures. Resuspension of dust was identified to be a major contributor of fine
particles indoors.
Particulate concentrations were measured for more than 48 hours in fourteen
households of Brisbane, Australia (Gilbert et al., 2005). A Condensation Particle Counter and
a Photometer were used to record the data. The occupants of all the households maintained an
activity diary so that their exposure to particulates could be determined. The highest
concentrations were recorded to be during the cooking time i.e. (47.5´103 particles/cm3) and
PM2.5 concentration (13.4 mg/m3). The highest residential exposure period was the sleeping
period for both particle number exposure (31%) and PM2.5 exposure (45.6%). The percentage
of the average residential particle exposure level in total 24h particle exposure level was
approximating 70% for both particle number and PM2.5 exposure.
Sources of aerosols vary greatly and Meng et al. (2005) studied the relationship
between sources generating aerosols outdoors, indoors and due to personal activities. 212
households were studied in three states of USA to investigate exposure to different pollutants
present in air including VOC’s, PM2.5, carbonyls and more. No smoker lived in any of these
houses and 162 of them were sampled twice. Median indoor, outdoor and personal PM2.5 mass
concentrations for the three sites were 14.4, 15.5 and 31.4 μg/m3, respectively. The
contribution towards PM2.5 concentrations indoors from outdoor sources was estimated to be
Chapter Two Literature Review
30
56% for all study homes i.e. 63% for California, 52% for New Jersey and 33% for Texas study
homes.
Chunram et al. (2007) studied the outdoor and indoor concentrations of PM2.5 in both
residential and workplace buildings. Monthly averages for indoor particulates ranged from
13.6 to 57.9 μg /m3 for residential building, while that for workplace building ranged from 9.9
to 58.5 μg /m3. On the other hand, monthly averages for outdoor PM2.5 ranged from 12.6 to
77.0 μg /m3 for residential building and that for workplace building measured between 15.1 to
70.0μg/m3. Ambient sources were found to contribute more to the PM2.5 concentrations
indoors.
Nature of work, number of occupants and type of ventilation system are responsible for
indoor air quality as found in a study by Helmis et al. in 2007. Indoor air quality in terms of
VOC’s, PM10, PM2.5, CO2, NOx and SO2 of a dental clinic was monitored for three months.
The highest exposure level was found to be during operation hours while non-working hours
showed to have the lowest levels. Moreover the nature of dental procedures and the material
used also affected the air quality. The effect of natural ventilation was also studied. It was
observed that increase in natural ventilation with the help of air renewal and double cross-
ventilation improved the indoor quality a lot.
Kurmi et al. (2008) studied the exposure of residents to particulate matter while doing
domestic work in both urban and rural areas of Nepal. 490 houses in urban and rural areas of
Kathmandu were monitored for respirable dust and PM2.5 over duration of 24 hours. The
average respirable dust proportion was measured to be 1400 µg/m³. On converting this
concentration to an 8-h time weighted average (TWA) it exceeded the UK limit of 4000 µg/m³.
Chapter Two Literature Review
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Women are more exposed to this high concentration of respirable dust which can result in
respiratory illness.
Exposure to fine particulate matter, polycyclic aromatic hydrocarbons (PAHs) and
black carbon (BC) was studied in a cohort of children of New York for a period of two weeks
after every six months (Jung et al., 2010). Indoor and outdoor levels were monitored between
October, 2005 and April, 2010 to study the impact of seasonal factors on pollutant
concentrations, and to analyse the relationship between ozone and PAH. The results showed a
distinct seasonal factor to be responsible for variations in pollutant levels during the heating
and non-heating seasons with elevated levels of PAHs and BC during the heating season while
PM2.5 levels did not suffer any significant change. The meteorological factors were also
responsible for varying emission rates of pollutants.
Residences are an important source of exposure to particulate matter and Bhangar et
al. (2011) studied seven residences from 2007-2009 to determine the factors and circumstances
responsible for exposure to ultra-fine particles. Cooking caused the greater variation in
exposure to ultra-fine particles.
IMPACT OF SEASONS UPON PARTICULATE MATTER
Seasonal variation along with indoor/outdoor ratios of PM, CO, NOx was observed in
eight households of Delhi, India by Kulshrestha and Khare (2011) with the conclusion that PM
levels were elevated during the colder months. The indoor outdoor ratio was also determined
and regression analysis revealed that indoor environment contributed significantly towards
higher PM and CO levels during the winters. Moreover, PM2.5 was observed to constitute a
higher proportion of RSPM in the indoor environment. The major sources for PM were
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32
identified to be the burning of biomass fuel and the cleaning activities carried out within the
houses.
Massey et al. (2012) studied the seasonal variations of PM10, PM5, PM2.5 and PM1 using
Grimm aerosol spectrometer in India. Five urban and five roadside sites were monitored from
October, 2007 till March, 2009. The respective average levels of PM10 indoor and outdoor
were recorded to be 247 μg/m3 and 255 μg/m3 at roadside houses while these levels being
181 μg/m3 and 195 μg/m3 at urban houses. Similarly the indoor and outdoor concentrations of
PM5.0 at roadside houses were 211 μg/m3 and 230 μg/m3 and at urban houses were 145 μg/m3
and 159 μg/m3 respectively. The annual mean concentrations of PM2.5 were measured to be
161 μg/m3 and 160 μg/m3 at roadside houses and 109 μg/m3 and 123 μg/m3 at urban houses.
PM1.0 concentrations at roadside houses were 111 μg/m3 and μg/m3 while at urban houses they
were 99 μg/m3 and 104 μg/m3 respectively. Seasonal variations of all above given particulates
was also studied and it was found that their levels increased prominently during the winter
season. Moreover an increase in pollutant concentration was highly correlated with an increase
in health problems, more prominent in houses with a higher concentration of fine particulates
(PM2.5).
The suburban residential micro-environments of UK were monitored by Nasir and
Colbeck (2013). The particulate matter levels were greatly affected by the activities and
ventilation practices. Cooking contributed to highest PM levels with smoking also playing a
significant part. Indoor smoking during the winter season doubled the PM levels. Cooking
practices were also observed to contribute towards varying PM concentrations as grilling led
to highest PM numbers followed by boiling and frying.
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Particulate matter levels in the indoor and ambient air along with bioaerosol levels were
investigated across four floors of a building in Seoul, Korea (Oh et al., 2015). The PM levels
were higher during the winter season than the summer season. The bioaerosol level were
highest on the fifth floor where a private academy school was being run. The microbial levels
were noted to vary by the number and activities of the students.
A research was conducted to assess PM2.5 and CO levels during the burning of
mosquito coils. The average PM2.5 levels were noted to be 1031 µg/m3 with mean CO levels to
be 6.50ppm. There was significant reduction in these levels (up to 50%) when the windows
were opened and further decline (90 %) when both the windows and doors were kept open
during the burning of mosquito coils. The average levels were reported to be higher than those
produced during biomass burning and can pose significant health risks. Although the results
were not statically significant, prevalence of respiratory problems was reported to be higher in
residents using mosquito coils (Salvi et al., 2015).
The influence of ambient PM2.5 levels was observed by Zhao et al. (2015) during the
haze-fog episodes in winters of Beijing. Continuous indoor and outdoor levels of PM2.5 were
recorded in a naturally ventilated building. A close relationship was observed between the
indoor and outdoor levels (r2 = 0.9104) when windows were closed and no indoor activity was
being performed. Ambient wind speed and relative humidity also showed a close correlation
with the indoor/outdoor PM2.5 ratios.
Harrison et al. (1997) monitored the concentrations of coarse and fine particles at a site
in Birmingham, U.K. from October, 1994 to 1995. Road traffic was identified as a major source
since it results in increased pollutant concentration not only through vehicular exhaust but also
resuspension of dust. A marked difference was observed during the winter and summer.
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34
PM2.5 comprised about 80% of coarse particles (PM10) during winter and was found to be
strongly correlated with NOx. On the other hand, coarse particles (PM10−PM2.5) accounted for
about 50% of PM10 during the summer season. Generation of coarse particles from re-
suspension depended positively on the wind speed while the elemental carbon from traffic was
negatively dependent on the wind speed.
Four sites {control(C), kerb (K), residential (R) and industrial location (I)} were
monitored in Mumbai city for concentration of fine particles in indoor and outdoor air using a
MiniVol PM2.5 sampler. Vehicular emissions were found to affect indoor air at the kerb site
while indoor sources were more contributing for IAQ at all sites. PAH concentrations were
elevated at all outdoor sources. OC percentage in PM2.5 was higher in indoor at control and
residential site, whereas EC percentage in PM2.5 was higher in kerb and control. Strong
correlation was observed between indoors and outdoors, EC and OC at kerb sites which
suggested that indoor concentrations were derived from outdoor environment (Joseph et al.,
2010).
The density of traffic on roads can significantly affect the indoor air quality of nearby
indoor microenvironments through infiltration. El-Batrawy (2011) studied the concentration
of PM10, NOx, and SOx at 22 houses which were located on streets with different traffic
densities. Measurements were made for both indoor and outdoor air quality during winter and
summer. Outdoor sources such as high traffic were found to contribute more to indoor air
quality. Coarse particle concentration increased in winter while NOx and SOx increased in
summer. An increase in I/O ratios was observed during the summer season indicating outdoor
sources to be more predominant during this season.
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35
Elemental and ionic composition of PM1 and PM2.5 were conducted after collecting
samples form old age homes in Antwerp. The samples were collected via impaction and
subjected to EDXRF spectrometry and IN for analysis. The ambient levels were higher than
the indoor levels. Zn and Pb were observed in higher concentrations. Moreover a strong
association was concluded between the indoor and outdoor environments. Since no significant
indoor source could be located, ambient sources were considered to be prevailing within the
old age houses (Buczyńska, et al., 2014).
Ambient sources have been concluded by many studies to have a substantial impact
upon IAQ and a recent study by Kearney et al. (2014) used the infiltration factors (Finf) to
better understand the exposure estimation within houses. Fine and ultrafine particles were
monitored in 74 houses of Edmonton during the winter and summer season. A parallel
monitoring of the subsequent outdoor and another ambient location was also carried out. The
Finf for fine particulate matter ranged between 0.10 and 0.92 during the winters while it was
0.31 to 0.99 in summers. The indoor contributors of fine and ultrafine particles were concluded
to be cooking and smoking. However, ambient sources still had a substantial impact in defining
the indoor air quality.
PM2.5 was sampled and collected on polytetrafluoroethylene filter paper from indoor
micro-environments at three sites (urban, rural and roadside). Highest levels were obtained
from the rural site (71.23 µg/m³) as compared to urban (45.33 µg/m³) and roadside location
(36.71 µg/m³). Elemental composition of PM2.5 was determined by inductively coupled plasma
atomic emission spectroscopy and Cadmium and Lead were found to have an association with
cancer risk (Varshney et al., 2015).
Chapter Two Literature Review
36
PARTICULATE MATTER EMISSIONS FROM COOKING
A study on four different types of stoves in use in kitchens of rural Guatemala was
conducted by Naeher et al. (2000). Observations were made for 22 hours in each of the three
houses for PM2.5, PM10, carbon monoxide and total suspended particulates (TSP) in the
kitchen, bedrooms and outdoors. The four different conditions of the kitchens used included
background type with no stove in use, kitchen having traditional open-wood stove, kitchen
with improved woodstove with flue also called plancha, and kitchen using LPG gas stoves. No
smoker lived in any of the test houses and a mother with a baby less than fifteen months old
was present in these houses. Personal measurements of the mothers and their babies were also
made as usually the mother carried her baby on her back during the daily household routine. It
was found that open wood-stoves gave the highest concentrations of all the above listed
pollutants; PM2.5 level was 528 µg/m3, PM10 as 717 µg /m3, TSP level was 836 µg /m3, and
CO had a concentration of 5.9 ppm. On the other hand, background had the lowest
concentration of PM2.5, PM10, TSP and CO i.e. 56 µg /m3, 173 µg /m3, 174 µg /m3, and 0.2 ppm
respectively. The respective levels of these pollutants in kitchens using plancha were 96 µg
/m3, 210 µg /m3, 276 µg /m3 and 1.4 ppm; while those for gas stoves were 57 µg/m3, 186 µg/m3,
218 µg/m3 and 1.2 ppm. Moreover personal measurements of PM2.5 and CO for mothers and
children showed the highest levels while using open wood-stoves and the lowest levels were
observed while using gas stoves.
In a study conducted by Lee et al. (2002) on indoor air quality within flats, it was
observed that the average concentrations of CO2 and PM10 over 8 hours in the kitchens were
14% and 67% higher than those measured in the living rooms. Moreover Liquefied Petroleum
Gas (LPG) stoves were found to be a more potent source of indoor VOC’s than stoves using
Chapter Two Literature Review
37
natural gas as fuel. Also the mean bacterial count in kitchens of most houses was 23 % more
than in the living rooms.
A study was conducted on six households in three different sites (roadside, urban and
rural) of Hong Kong to determine the indoor/outdoor relationship for PM2.5 and carbonaceous
pollutants (Cao et al., 2005). 24h mean concentrations of indoor and outdoor PM2.5 were
measured to be 56.7 and 43.8 μg /m3 respectively. The average concentrations of organic
carbon (OC) and elemental carbon (EC) were measured to be 17.1 and 2.8 μg /m3 respectively.
The contribution of OC towards PM2.5 was 29.5 % while EC contributed 5.2%. It was observed
that while ambient sources contributed more towards PM2.5 indoors, daily activities in houses
also resulted in episodic increase in PM2.5 levels. Also, 2/3rd of carbonaceous pollutants indoors
had their sources outdoors.
He et al. in 2004 studied PM2.5 concentrations and sub micrometer particles in kitchens
of 15 houses of Brisbane. Twenty one types of indoor activities were identified using activity
diaries filled by the occupants. It was found that the level of sub micrometer particles was
elevated as high up to five times during frying, grilling, stove use, cooking, fan heater, candle
vaporizing eucalyptus oil etc. on the other hand smoking, frying and grilling caused an increase
in levels of PM2.5 up to 3, 30 and 90 times higher than background levels.
The impact of improved stoves on particulate concentrations was studied by
Chowdhury et al. (2008) in rural highland Guatemala. PM2.5 and PM1 concentrations were
monitored for 48 hours in the kitchen, bedroom and outdoors of selected houses. In kitchens
with the traditional open fire stoves, PM2.5 concentrations were 1093 ± 906 μg/m3 while this
value decreased to 81 ± 181 μg/m3 in kitchens with improved stoves with chimneys. Similarly
there was 64 % reduction in particulate concentrations in the bedrooms of houses with
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38
improved stoves and 69 % reduction in outdoor concentrations. Moreover for PM1, 91 %
reduction was recorded in the kitchens with improved stoves as compared to kitchens with
open fire. However there was not a significant difference of PM1 concentrations in the
bedrooms and outdoor environment of both types of houses. Thus improved chimney stoves
were helpful in reducing particulate pollution indoors.
Improved stoves can reduce the concentration of PM2.5 indoors (Ward and Noonan,
2008). USEPA certified stoves were distributed in a Rocky Mountain valley community to
replace old wood stoves. PM2.5 concentrations were monitored using DustTrak aerosol monitor
in sixteen hoses before and after the intervention. Organic carbon, elemental carbon and other
chemicals from wood smoke were also measured from quartz filters. A significant reduction
(71 %) was observed in the average concentration of fine particulate matter after the
introduction of improved stoves. Resin acids (natural chemicals in bark of wood) were found
to increase while Levoglucosan also decreased by 45 %.
There is a wide variety in how you cook your food. Whichever the cooking method
may be, there is always a significant generation of particulate matter to the surrounding air and
exposure to high levels of PM have been documented to cause adverse health effects.
Buonanno et al. (2009) conducted a study to characterise the PM emissions caused by various
factors during cooking such as the type of food being cooked, type of oil used for cooking, and
also cooking temperature. Increased temperatures led to increased emissions. Moreover
cooking vegetables was observed to contribute less towards general PM loads than the cooking
of fatty foods. Olive oil was found out to be the best for frying in terms of lowest PM emissions
while cooking on a hot plate emitted lower amounts of PM than the gas stove.
Chapter Two Literature Review
39
The type of biomass fuel burned is also an indicator of the amount of PM released into
the surrounding air as concluded by Ansari et al. (2010) in their study. A rural area of Lucknow,
India was selected for the monitoring. Two categories of houses were defined on the basis of
the type of biomass fuel in use. One group burned plant material only while the other group
employed all kinds of biomass fuel to carry on with their work. PM2.5 and PM10 were monitored
along with Polyaromatic Hydrocarbons (PAH) emissions from different fuel types. An obvious
difference was noted during the cooking and non-cooking periods. The respective average
concentrations of PM2.5 and PAHs ranged from 1.19 ± 0.29 to 2.38 ± 0.35 and 6.21 ± 1.54 to
12.43 ± 1.15 μg/m3 during cooking while the respective PM10 and total PAHs mean levels were
in the range of 3.95 ± 1.21 to 8.81 ± 0.78 and 7.75 ± 1.42 to 15.77 ± 1.05 μg/m3.
Huboyo et al. (2011) studied different cooking methods to determine which method
emitted the highest concentrations of PM2.5 and carbon monoxide. Frying caused the highest
levels of PM2.5 indoors while boiling emitted the lowest concentration.
Shimada and Matsuoka (2011) studied the prevalence of PM2.5 in houses using solid
biomass fuels in fifteen Asian countries. Moreover since people stay indoors for different time
durations, their exposure to PM2.5 indoors was also studied. The highest exposure concentration
of 427.5 μg/m3 was observed in China. Nepal came second with an average concentration of
285.2 μg/m3 while Laos and India had an average exposure concentration of 266.3 μg/m3 and
205.7 μg/m3 respectively. Children and women, especially housewives between ages 35-64
were found to be more exposed to PM2.5.
Another study on the impact of improved stoves upon PM levels in Bangladesh was
conducted by Chowdhury et al. (2012). A reduction in levels of indoor particulate matter and
carbon monoxide emissions was observed. This also reduced the exposure risk of the cook.
Chapter Two Literature Review
40
The chemical composition of the PM2.5 fraction generated by burning biomass fuel consisted
of organic matter (59-60%) and elemental carbon (29-30%).
PARTICULATE MATTER AND ENVIRONMENTAL TOBACCO SMOKE
Smoking is also a major source of PM2.5 and PM1 and affects not only the smokers but
also other people around them. While smoking is harmful for the health of the smoker, second
hand smoke poses threats for the non-smokers present around. Laws imposing a ban on
smoking in public places have been found to be useful in reducing concentrations of fine
particles indoors.
Neas et al. (1994) studied the effect of passive environmental tobacco smoke on white
children aged 7-11 years. It was found out that additional cigarette packs smoked per day
within houses increased the incidence of lower respiratory diseases in children. Moreover, the
average PM2.5 concentration in houses with smoking was 48.5 μg/m3; while in houses without
smoking it was 17.3 μg/m3. However PM2.5 was not found to have any direct effect on
children’s pulmonary function. Thus exposure to PM2.5 was weakly associated with decreased
pulmonary function in preadolescent children.
Goodman et al. (2007) studied the effect of ban on smoking in public places on the
health of barmen in Dublin. Second hand smoke affects the health of nonsmokers greatly and
this study focused on the impact of ban on smoking in public places. Forty two bars were
monitored for PM10 and PM2.5 concentrations before the ban was imposed in 2004, and a year
after the ban. Similarly benzene concentrations in 26 bars were also monitored. Eighty one
barmen were questioned and their pulmonary function was examined along with salivary
cotinine. It was revealed that the ban had a positive impact on the health of the workers while
the air quality of the pubs had also improved tremendously in one year. An improvement in
Chapter Two Literature Review
41
the pulmonary function tests was observed with a 79 % decrease in exhaled breath carbon
monoxide and an 81 % decrease in salivary cotinine. Moreover an 83 % reduction in PM2.5 and
80.2% decrease in benzene levels were a clear cut indication of improved air quality of the
bars.
In a similar study, real time monitoring of PM2.5 was done at nine hospitality sites and
a hall of Georgetown, Kentucky before and after the implementation of a ban on smoking in
public places (Lee et al., 2007). Measurements were made before and after the ban and a
significant decrease in PM2.5 levels was observed at all the nine restaurants selected. However,
no difference was observed at the bingo hall due to non-compliance of the law. However after
three months, the PM2.5 levels dropped to 43μg/m3 as the law was enforced then.
Forty public places of Rome were monitored by Valente et al. (2007) for PM2.5 and
PM1 before and after a ban on smoking in public places was imposed in 2005. The
concentration of PM2.5 was 119.3 μg/m3 before the ban which then decreased to a mean value
of 38.2 μg/m3 within three months after the ban. A year later this value was measured to be
43.3 μg/m3. Similarly the mean concentration of ultra-fine particles (PM1) showed a significant
decline from 76,956 particles/cm3 to 38,079 particles/cm3 in three months and then to 51 692
particles/cm3 after a year. Moreover the level of cotinine (a metabolic by-product of nicotine)
in urine of non-smoking workers also decreased from 17.8 ng/ml to 5.5 ng/ml and then to 3.7
ng/ml (p<0.0001). Thus a reduction in mean concentrations of PM2.5 and PM1 was observed
after the imposition of ban on smoking.
Hyland et al. (2008) carried out a study to observe the PM levels generated by
environmental tobacco smoke (ETS) in thirty two countries. It was observed that in countries
where there was a ban on smoking in indoor public areas, particulate concentrations were found
Chapter Two Literature Review
42
to be much lower. Indoor air was sampled at a total of 1822 venues out of which 584 sites were
smoke free and the remaining 1238 venues had no restriction on smoking indoors. The PM2.5
mean concentration was observed to be 21 µg/m³ at smoke-free sites (ranging from 0 to 573
µg/m³) while it was 188 µg/m³ at smoking sites (ranging from 1 to 3764 µg/m³). New Zealand
had the lowest concentration at 8 µg/m³ while highest level was observed in Syria (372 µg/m³).
Fine particulate concentration was observed to be 8.9 times higher in places where smoking
was allowed than the smoke-free areas on the average.
Lee et al. (2010) studied the concentrations of PM2.5 due to second hand smoke in seven
Asian countries. Environmental Tobacco Smoke (ETS) is a major threat to health and second
hand smoke can cause health problems in non-smokers too. In this study, four types of public
places were selected i.e. restaurant, café, bar/club and entertainment sites in China, India,
Japan, Korea, Malaysia, Pakistan and Sri Lanka. Real time analysis of PM2.5 was carried out at
a total of 168 hospitality sites in these seven countries. The average concentration of PM2.5 was
137 μg/m3, with Malaysia having a mean concentration of 46 μg/m3 to India having 207 μg/m3.
In smoking venues, this value was 3.6 times higher (156 μg/m3) than in non-smoking areas (43
μg/m3). There must be some effective legislation for a ban on smoking in Asian countries to
improve the air quality and health of people also.
Tobacco smoke is known to contain a wide assortment of chemicals and elements in it
that are injurious to health. A recent study by Ruggieri et al. (2014) investigated the levels of
heavy metals in indoor PM2.5 levels in 73 houses of South Italy. Gravimetric sampling was
conducted using Teflon filters which were then analyzed for heavy metal content. Higher levels
of Cadmium and Thallium were detected in houses where smokers were present.
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On the contrary, Bilocca et al. (2014) did not find any significant relation of Cadmium
and Thallium levels with smoking. Particulate matter was sampled in 45 homes to identify the
presence of heavy metals. Moreover, association between exposure to second hand smoke and
asthma in children was also investigated. Greater exposure to second hand smoking was
associated with asthma but sources of Cadmium and Thallium levels in fine particulate matter
were not found to be associated with smoking habits.
IMPACT OF PARTICULATE MATTER UPON WELL-BEING OF PUBLIC
Many studies have documented the health effects of particulate matter on human beings
and it has been concluded that exposure to PM leads to lung cancer, respiratory illness and
cardio-pulmonary disorders. Mishra (2003) conducted a study on the prevalence of Acute
Respiratory Infections (ARI) in children below five years of age in Zimbabwe. The study was
based on 3,559 children included in the 1999 Zimbabwe Demographic and Health Survey
(ZDHS). Among the 66 % children who live in houses using biomass fuel, 16 % suffered with
acute respiratory infections. After adjusting for different factors, it was found that children in
houses with biomass fuel were twice more prone to respiratory infections as compared to
children in those households where natural gas/LPG or electricity was being used as a fuel.
Since ambient particles can increase blood pressure, a study was conducted by
McCracken et al. (2007) in Guatemala on the effect of improved stoves on women. Two groups
were formed: the control group used the traditional open wood-fire stoves, and the intervention
group which used improved stoves with chimneys (also called a plancha). The average
concentration of PM2.5 was measured to be 264 μg/m3 in the control group and 102 μg/m3 in
the intervention group. Moreover blood pressure was also measured and a decrease in the blood
pressure of subjects of intervention group was observed. The systolic blood pressure was 3.7
Chapter Two Literature Review
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mm Hg lower than the control group while the diastolic blood pressure was 3.0 mm Hg lower
than the control group. Similarly the subjects of intervention group showed a difference in
blood pressure before and after the use of plancha stove.
More recently the effect of PM exposure on mitochondrial activity was studied for the
first time by (Hou et al., 2010). Steel workers in Italy were selected for the study to observe if
incresed exposure to PM lead to incresed mitochondrial DNA copy number which determines
mitochondrial damage. Real time PCR was carried out on day 1 and day 4 in a week to observe
mitochondrial DNA copy number along with measurement of personal exposure to various
fractions of particulate matter. Higher number of mitochondrial DNA copy numbers were
observed on day 4 which lead to the conclusion that oxidative stress is produced as a result of
damaged mitochondria linked with excessive exposure to PM.
MICROFLORA OF INDOOR AIR
Air-borne microorganisms i.e. bacteria and fungi are also a type of indoor air pollutant
and rather a more threatening type as they are responsible for a variety of diseases such as
tuberculosis, fever, nausea, asthma, legionellosis, diphtheria and many more (Di Giorgio et al.,
1996 and Jones, 1999). Indoor micro-flora is reported to be responsible for health problems,
especially among children (Maus et al., 2001). The major factors responsible for micro-
organisms to spread in indoor environment is considered to be the activities of people, air
conditioning systems, animals, plants, material used for construction and particles of dust and
soil (Goddard, 1964).
Air sampling was carried out in Dutch houses, libraries, offices and schools to identify
the airborne myco-flora of these non-industrial indoor environments. Surface sampling was
done by swabs and cello tape preparations while a RCS-Reuter centrifugal air sampler was
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also used. Among the species identified, the most common ones included Aspergillus
versicolor, Cladosporium spp., Penicillium brevicompactum, Penicillium chrysogenum,
Eurotium spp. and Wallemia sebi with occasional presence of Aspergillus fumigatus,
Scopulariopsis spp. and Stachybotrium spp. it was suggested that both air and surface sampling
should be employed side by side as it ensures the isolation of species left by one method (van
Reenen-Hoekstra et al., 1991).
The concentration of fungi in six apartments of Taipei was measured using Two-stage
Andersen viable impactor (Li and Kuo, 1993). There was a difference in the concentration of
fungi in different rooms of the apartments including kitchens and living rooms also. Moreover,
more than 80 % of fungi present were respirable. Concentrations of Aspergillus, Penicillium
and Cladosporium were found to be more than 500 cfu/m3.
Indoor and outdoor fungal concentrations in Yokohama, Japan were assessed by
(Takahashi, 1997) using a Reuter centrifugal air sampler. Highest ambient averages were
obtained during September and in October in the indoor air. Cladosporium spp. Alternaria spp.
and Penicillium spp. were observed in greater amounts in the ambient air while in the indoor
micro-environments, dominant species were Cladosporium spp., Aspergillus restrictus,
Wallemia sebi, A. glaucus, and Penicillium spp. a significant correlation was revealed between
the fungal composition and physical parameters such as temperature, wind velocity, relative
humidity and precipitation.
A study conducted by Pastuszka et al. (2000) on bio-aerosols in different homes and
offices in Poland revealed that concentration of Penicillium constituted of 90% of the total
fungi in moldy homes while it ranged from 3 to 50 % in healthy homes. Also the concentration
of fungal spores differed with seasons: in winter the concentration was found to be 10 to 102
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cfu/m3 in healthy homes and 10 to 103 cfu/m3 in moldy homes. On the other hand these levels
rose to 103 cfu/m3 in healthy homes and 103–104 cfu/m3 in houses with molds in summer. The
typical level of air borne bacteria was found to be 103 cfu/m3 in homes and 102 cfu/m3 in
offices. Moreover Micrococcus spp was found in all homes comprising 36 % of the total
bacterial genera while Staphylococcus epidermidis was found in majority of houses being the
second most common species.
Pei-Chih et al. (2000) studied air-borne fungal concentrations in urban and sub-urban
houses in southern Taiwan. Air samples were collected with the help of Burkard sampler and
their concentrations of fungi calculated as cfu/m3. It was observed that the fungal
concentrations were significantly higher in sub-urban houses during the summer season.
Cladosporium and Penicillium were found to be the dominant species resulting in such high
concentrations indoors and outdoors respectively. The mean concentrations of airborne fungi
indoors were 8946 cfu/m3 in winter and 4381 cfu/m3 in summer. The outdoor concentrations
were found to be 11464 cfu/m3 in winter and 4689 cfu/m3 in summer. Moreover in suburban
areas Penicillium was abundant during the winter season while Aspergillus was dominant
during the summer.
Air conditioners (AC) are most commonly used to create a comfortable indoor
environment but they are also a source of microbial contaminants. In a study by Hamada and
Fujita (2002), it was observed that fungal contamination increased about five times more than
that caused by carpets. Inside the filters of AC, Cladosporium and Penicillium were dominating
species. Moreover the air conditioners used on regular basis resulted in a higher number of
fungal species in the air than in rooms where AC was not so frequently used. Interestingly, the
fungal contamination peaked when the AC was switched on but decreased over time.
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Relationship between air-borne and dust-borne fungi was assessed as fungal samples
are mostly collected from these two sources. Air samples were collected from November 1994
to September 1996 using a Burkard culture plate sampler. The sample size was 496 homes and
sampling was done in the bedrooms. Dust samples were collected on cellulose extraction using
a vacuum cleaner. The dust was sieved and dilution plated onto DG-18 media. There was not
a significant association between the dust-borne and air-borne fungal species except for
Cladosporium and Penicillium. Presence of carpets and also the type of house were indicative
of the dust-borne fungi while infiltration from outdoor air indicated the type of airborne fungi.
Due to a weak relationship between the two types of sampling, it is important to collect samples
from both sources to have a more comprehensive understanding of the exposure risk present
for the inhabitants (Chew et al., 2003).
Hargreaves et al. (2003) studied the association between air-borne fungi and particulate
matter in fourteen houses of Brisbane. The average fungal colony forming units outdoors and
indoors were 1133+759 and 810+389, respectively. Under normal ventilation conditions, the
average outdoor and indoor concentrations of sub micrometer was 23.8 x 103and 21.7 x 103
(particles/cm3). On the other hand, super micrometer average concentration of outdoors and
indoors was 1.78 and 1.74 (particles/cm3), respectively. Moreover there was a direct relation
of concentration of fungal spores with a nearby source i.e. a park. In houses adjacent to the
park, fungal concentrations were found to rise up to about 3100 cfu/m3 and in houses at a
distance of 150 m or more from a park the cfu/m3 was below 1000. There was a lack of
significant association fungal concentrations and PM2.5 while a weak relation was observed
between the fugal levels and supermicrometer particles. However there are not many studies
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to date which have tried to correlate bioaerosol levels with particulate matter in the indoor
environment and much work needs to be done in this context.
Concentrations of fungal spores and particulate matter in the air were measured during
renovation in a building. Suspended dust was measured to be 6.1 mg/m3 while particulate
sulfate (SO42−), nitrate (NO3
−), chloride (Cl−), ammonium (NH4+) and lead were recorded to be
2960, 28, 1350, 100 and 13.3 µg/m3, respectively. Air borne fungi and fungal spores were
measured to be 1.11 × 106 colony forming unit per gram. The dominant fungal species were
Cladosporium (33%), Aspergillus (25.6%), Alternaria (11.2%) and Penicillium (6.6%).
Renovation activities should therefore be carried out with precautions so that it does not
infiltrate into the occupied area and affect the people residing (Abdel Hameed et al., 2004).
Airborne fungal spores are responsible for a variety of respiratory problems including
asthma. A study was conducted to measure the concentrations of fungi in the ambient and
indoor air of houses of children affected with asthma (n = 414). The indoor fungal levels
correlated significantly with the outdoor levels and were related with the level of dampness in
the house, presence of cat and cockroaches (O’Connor et al., 2004).
A number of health problems have been reported in houses experiencing water and
mold damage. Children are more susceptible to these risk factors present around them and a
study was conducted to investigate the relation existing between the prevalence of lower
respiratory tract infection and allergies with that of visible mold or water damage. The selected
houses (having children at age of 8 months) were visited to check the mold and/or water
damage in the building. The health record of the infants was also investigated. Half of the
houses surveyed had a mold and/or moisture problem with the situation being worse in about
5 % of the houses which twice increased the risk of recurrent wheezing in children. Moreover
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this risk increased 5 to 6 times in infants with food or aero-allergen sensitization. It was
concluded that recurrent wheezing in infants was significantly associated with the presence of
water and mold damage in houses (Cho et al., 2006).
The levels of microbial species in the air were determined in a Korean high-rise
building. The ambient levels of bacteria were higher in lower floors than in higher floors while
the indoor levels in the lower and higher apartments did not differ much. The seasonal variation
was also distinct with higher concentrations during the summers as compared to the colder
months. Among the fungal fauna, four dominant genera were detected i.e. Cladosporium,
Penicillium, Aspergillus and Alternaria with Cladosporium found in higher levels in the
kitchens as compared to other rooms (Lee and Jo, 2006).
Sampling was carried out in and outside of six mold free homes in Cincinnati area using
a Button Personal Inhalable Aerosol Sampler. Sampling was done for 24 hours during three
seasons. The average colony forming units of fungi in the ambient air were 102 while in the
indoor air, 88 colony forming units were observed. A total of 26 culturable fungal genera were
identified in the indoor and outdoor samples. Indoor environment was found to be more
favourable for the survival of fungal species. There was a significant correlation between the
indoor and outdoor levels of total spores and culturable fungi. Cladosporium, Aspergillus, and
Penicillium were more commonly found with highest culturability observed during the autumn
season. Increased culturability means an increase in release of allergens and is an important
factor to be considered for human health (Lee et al., 2006).
Alternaria alternata is a common fungal species present in the indoor air and exposure
to it may cause asthma. To study the relationship between exposure to Alternaria as a causative
agent of asthma, dust samples were collected from 831 households in 75 locations throughout
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US. Samples were collected from the kitchens, bedrooms, and living rooms of the study sites
and questionnaires were filled for each site to gain information about the health of the
occupants, building structure and demographics. The results concluded that increase in asthma
symptoms was observed with an increase in exposure to A. alternata in US homes (Salo et al.,
2006).
A study was conducted in Austria to observe the growth of mold in 66 households and
the presence of fungal spores in the air. Among the selected households, 29 had no visible
mold growth while the remaining 37 houses showed signs of mold growth. One-stage MAS-
100® sir sampler was employed to collect samples with Malt Extract Agar and Dichloran
Glycerol Agar as culture media. The number of air-borne fungal spores was much higher in
buildings with a visible mold problem than in buildings with no visible mold growth. Also it
was noted that the air-borne microflora of the houses without a visible mold growth resembled
that of the outdoor air. Penicillium and Aspergillus were found to be the dominant part of the
recorded micro-flora indoors in houses with the mold problem (Haas et al., 2007).
The baseline concentrations of air-borne myco-flora were determined in 100 office
buildings in the US during 1994-1998 as a part of the BASE study. A large number of samples
were taken for different time periods, at different sites, and at different times of the day.
Comparisons were made between fungal species observed indoors and outdoors, during
different seasons and using different sampling methods. More fungal groups were observed
during the summers than in winters (Tsai et al., 2007).
The types and levels of fungal species present in air-conditioned rooms in 18 single
family homes were determined. There was no visible or reported moisture and/or mold
damage. Two samples were collected from the outdoor air while three indoor samples were
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collected at each site. Indoor levels were observed to be lower than the ambient levels. The
most dominant spore types belonged to Penicillium and Aspergillus genera while Ascospores
and basidiospores were in higher numbers in the outdoor air. Apart from these species,
Chaetomium, Stachybotrys, and Ulocladium species which are indicator of moisture were not
present in significant numbers (Codina et al., 2008).
We are exposed to a variety of microbes present in the indoor air at all times. The
bacterial flora in the dust samples was analyzed from two buildings over a year during the four
seasons. It was observed that gram positive species were the predominant components of the
indoor dust. The bacterial flora varied during the seasons as well as in both buildings. The
occupants of the buildings were identified as the direct source of the dominant phylotypes
(Rintala et al., 2008).
The indoor air of two restaurants in Hong Kong was sampled for bacterial species. A
total of 15 genera were identified using MIDI, Biolog, and Riboprinter. The most common
species were Gram-positive bacteria with Micrococcus and Bacillus species being most
abundant. Majority of the species were opportunistic pathogens but their indoor level was
below the recommended level of Hong Kong Indoor Air Objective (< 500 cfu/m3). The
identified species were representative of species found in the soil, respiratory system of
humans and skin (Chan et al., 2009).
Fungal contamination was examined in 118 buildings in Eastern France. Among the
sample size, 32 buildings had a visible mold problem and self-reported health problems by the
occupants; 27 dwellings were occupied by medically diagnosed allergic patients; and 59
residencies served as the control group. The most abundant species were identified to belong
to Aspergillus, Penicillium, and Cladosporium genera. In the buildings occupied by allergy
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patients, Penicillium chrysogenum and Penicillium olsoni were found to be in higher numbers
than any other species (Reboux et al., 2009).
The presence of fungal spores in the indoor environment is related to a vast number of
factors among which the home characteristics are also noteworthy. A study was conducted in
Cincinnati, Ohio to investigate the fungal loads in an indoor environment (Cho et al., 2006).
For this purpose, 777 homes were selected for an ongoing birth cohort study. On-site inspection
of the homes was carried out to detect any visible mold problem along with filling of
questionnaires for relevant information. Analysis of cat, house dust mite, and cockroach
allergens was done using monoclonal antibodies while polyclonal antibodies were used for
Alternaria and dog antigens. Water damage and mold problems were present in more than half
the number of homes while above 90% homes were carpeted. However presence of Alternaria
in dust was not associated with visible mold damage but was related to presence of dogs in
homes. Houses with increased humidity were also affected with elevated levels of Alternaria
antigen.
Frankel and colleagues (2012) conducted an investigation to evaluate air-borne content
of microbes during varying seasons with different temperature and humidity levels. Dust
samples were collected from five Danish homes during different seasons. It was observed that
fungal levels were highest during the summer season while bacteria reached the peak during
spring season. Moreover, fungi were higher in concentrations in the outdoor air while the
bacterial levels along with endotoxins were elevated in the indoor air. A direct association
between fungi and temperature and humidity existed while the case was opposite for bacteria.
It was concluded that indoor microbial levels were influenced significantly by temperature,
relative humidity, and ventilation rates as well along with seasonal variation.
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Fungal diversity and composition in indoor air was assessed during the summer and
winter season (Adams et al., 2013) in a university housing facility. A seasonal variability was
observed in fugal levels being stronger in the ambient air. It was concluded that outdoor
composition of fungal species affected the indoor levels.
Joshi and Srivastava (2013) exposed sterile petri plates coated with nutrient Agar and
Potato Dextrose Agar in residencies to record the micro-flora of indoor environments. The
plates were then incubated at 25oC for 48 hours for bacterial cultures and five days for fungal
cultures to allow growth of colonies. A Polymerase chain reaction (PCR) based method was
employed for the detection of microbes. The common constituent bacterial species in the
indoor air were identified to be Brevibacillus brevis, Arthrobacter spp. and Bacillus cereus
while the fungal biota comprised of Neosartorya fischeri, Aspergillus clavatus and
Trichoderma reesei in the indoor air.
AIR QUALITY IN PAKISTAN
Data on indoor air quality in Pakistan is rather scarce. Indoor air pollution is not given
much importance in the country as it is not considered as a hazard by the policy makers. So far
the Pak-EPA has not yet established any guidelines for PM and bioaerosol levels in the indoor
environment. It is therefore of prime importance that IAQ is studied widely and research on
source appointment conducted. The condition of ambient air quality in Pakistan is also
deteriorating at a fast pace and the policy makers should attend to these issues on a priority
basis as the mortality ratios in Pakistan are alarming. Limited data is available on microbial
composition of air in Pakistan. There are a few studies which have documented microflora of
the indoor air while some other researchers have recorded micro-biota of the ambient air.
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The air borne micro-flora of Karachi University was studied resulting in identification
of 53 species of fungi in the air. For this purpose glass slides smeared with glycerin were
exposed at varying heights of 1.5 m, 5 m, and 10 m. The exposure time was 24 hours after
which the slides were observed under a microscope. At lower altitude of 1.5 m, 36.22 % fungal
species were observed while the highest proportion of 39.9 % fungal species was found at a
height of 5 m from the ground surface. The remaining 23.86% of myco-flora was obtained
from higher altitude (10 m). Thirteen species belonging to the genus Aspergillus were recorded
in the air making it the most prevalent fungal species present in the air. Apart from Aspergillus,
species of Alternaria, Penicillium, and Cladosporium were also present in large numbers
(Afzal and Mehdi, 2002)
The microbial flora of the ambient air in Karachi was observed during 1998-1999 using
settle plates. The agar coated plates were exposed for five minutes each at different times of
the day. A total of 53 fungal species were identified belonging to 21 genera. A decrease in
number of air-borne fungal colonies was observed during the winter months, particularly
January while the warmer months displayed an increase in fungal levels. It was observed that
the fungal content had a direct relationship with relative humidity and an inverse relationship
with temperature. However the sampling method and agar media used for sampling can result
in variations in results (Afzal et al., 2004).
In another study on airborne microflora of Karachi, similar observations were made in
context with the seasonal variation. A higher concentration of fungal spores was observed
during the summer season as compared to winter. Spore trapper technique was employed along
with exposing of agar coated petri plates in five sampling sites. The most common species
identified belonged to genus Aspergillus such as Aspergillus fumigatus, A. niger, A. flavus, A.
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candidis, A. terreus, and A. wentii. Apart from them, Alternaria solani, Penicillium notatum,
and Drechslera dematioidea were also notable (Rao et al., 2009).
In an investigation of indoor air quality of rural and urban sites in Pakistan, Nasir et al,
(2012) found that 55 to 99% of the observed micro-organisms were below 4.7mm in size and
therefore capable of entering the lower respiratory tract. The maximum concentration of
culturable bacteria was 14,650 cfu/m3 in the indoor environment in contrast to 16,416 cfu/m3
in the ambient air.
A recent study by Sidra et al. (2015) observed the impact of activities upon bioaerosol
levels. Agar coated petri plates were exposed in the kitchens and living rooms of five
residential houses of Lahore, Pakistan for twenty minutes each. Plates were exposed in the
presence of domestic activities being carried out in the rooms and another set was exposed an
hour after the last activity had been carried out. The results concluded that bioaerosol levels
were higher when there was activity in the rooms while decreased significantly when there was
no work being done in the kitchens or living rooms.
Siddiqui et al. (2005a) conducted an investigation to check the prevalence of ocular
and respiratory maladies in rural women who burned solid fuels for cooking purpose. A strong
association was observed to exist between the two factors. Similarly, in another study, Siddiqui
et al. (2005b) observed that exposure of pregnant females to smoke generated by wood burning
for cooking resulted in low birth weight of the infants.
The use of solid bio-mass fuels results in poor indoor air quality and thus is a serious
health issue in the developing countries. Biomass fuel is widely used as cooking fuel in rural
Pakistan. Colbeck et al. (2008) studied the indoor air quality of some rural and urban areas of
Pakistan in terms of PM10, PM2.5, PM1 and bioaerosols. The concentration of PM10 within
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kitchens using biomass as fuel was up to 8,555 μg/m3. Smoking and cooking contributed to
high values of particulate matter. Moreover the bioaerosols belonged to the respirable fraction.
Wood is used as a fuel in many rural areas of Pakistan and exposure to the arising pollutants
from wood smoke during the prenatal period can reduce birth weight in babies. Siddiqui et al.
(2008) obtained the birth weight of babies whose mothers used wood as a fuel and also those
using natural gas. A significant association was observed between exposure of pregnant
females to PM2.5 during wood burning and consequent low birth weight in infants.
PM2.5 and CO concentrations were measured by Siddiqui et al. (2009) in a semi-rural
community in Pakistan. 51 kitchens using wood as a fuel and 44 kitchens using natural gas
were selected and monitored for eight hours daily from December, 2005 to April, 2006. Mean
concentration for CO was 29.4 ppm in kitchens using wood while in kitchens using natural
gas, the CO concentration was 7.5 ppm. Similarly in kitchens using wood, PM2.5 concentrations
were again higher i.e. 2.74 mg/m3 than the natural gas users where this value was only 0.38
mg/m3. It was concluded that wood as a source of fuel was hazardous for health in terms of
higher emissions of CO and PM2.5.
Colbeck et al. (2010) conducted a study to understand the variations in indoor/outdoor
ratios of PM10, PM2.5 and PM1 in both rural and urban sites in Pakistan. Since women and
children spend more time indoors, particularly in the kitchen, they are more exposed to
particulate pollution indoors. In rural areas where biomass was used as a major source of fuel,
the respective indoor/outdoor ratios for PM10, PM2.5 and PM1 in the kitchen were 3.80, 4.36
and 4.11. In the living room, these ratios were 1.74, 2.49 and 3.01. At the urban site, these
ratios were 1.71, 2.88 and 3.47. The concentration of particulate matter in rural kitchens was
recorded to be high, in the range of 4000-8555 μg/m3.
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Nafees et al. (2011) carried out a study at twenty different enclosed public places of
Karachi, Pakistan and observed that second hand smoke was a major contributor of PM2.5
indoors. The mean level of the fine particles was measured to be 138.8 μg/m3 (+ 112.8) with
the highest level being in the snooker/billiards clubs i.e. 264.7 μg/m3 (+ 85.4) and lowest value
at the restaurants (66.4 μg/m3 + 57.6). Moreover the smoking density was highest at the
snooker/billiards clubs.
Seasonal variation in PM levels was studied by Nasir et al. (2013) in rural kitchens. It
is a common practice in rural areas to construct outdoor open and semi-open kitchens for the
summer season. As a result of this practice, PM levels fell considerably in summers than in
winters where indoor kitchen was in use. Moreover, fuel choice also played an important role
in determining air quality in kitchens as natural gas resulted in lower PM levels than biomass
fuel. It was suggested that improvement of ventilation in kitchens can improve the air quality.
Although biomass burning as fuel leads to a poor air quality and associated health outcomes in
the cooks, it is still a major form of fuel used for cooking and heating purposes. Nasir et al.
(2015a) assessed the varying factors which play a detrimental role in fuel choice. Apart from
poverty being indicated as the prime reason for opting solid fuels, location of the household
and access to basic facilities were also observed to be important.
Cooking can be a major source of indoor particulate matter pollution. A study
conducted by Saeed et al. (2015) supports the impression. The levels of PM2.5 in the kitchens
are significantly determined by the location of the stove, ventilation designs and the fuel used
for cooking. The levels of PM2.5 in urban and rural kitchens were monitored by a real time
aerosol monitor for a comparative analysis. The findings of the research declared natural gas
and LPG as cleaner fuels in urban kitchen as compared to the cow dung and wood cast-off in
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58
rural kitchen. Highest levels of CO produced during wood, cow dung burning endorses poor
ventilation and ill health of the space.
Burning of solid fuels is a significant contributor towards indoor air pollution. A recent
research by Nasir et al. (2015b) monitored the number concentration of ultrafine particulate
matter in urban and rural houses using different fuels. Sampling was conducted in the kitchens,
living rooms and courtyards of two rural and one urban site using Condensation Particle
Counters. The 24-hour average levels were higher in the ambient air. Generally, the number
concentration was greater in kitchens burning natural gas as a fuel at the urban site than in
kitchens burning solid fuel and natural gas at the rural sites. However, at the two rural sites,
higher numbers were noted in kitchen burning biomass fuel rather than the one using natural
gas. Number concentration in the ambient air was higher at rural sites than the urban location.
The female community in the rural areas of under developing countries such as Pakistan
is highly exposed to PM pollution and thereby to increased health hazards. Amanat et al. (2015)
studied the PM2.5 emission from the different fuels used by the rural community in a country
area of Kasur district, Pakistan. Three rural houses were selected on the base of fuel being
used. One house was consuming wood and while other two were using wood as an energy
source. Smoking was found to be one of vital factor for aggregating PM levels up to 48 times
than the recommended WHO limit of 25 µg/m³.
The building designs, location and ventilation strategy seems to play an important role
while talking about the environmental health of a residential area. Particularly, the role of
ventilation has been discussed various times while defining air quality in the indoor
environments. Abbas et al. (2015) discussed the association of indoor air quality with outdoor
air in context of ventilation. To do so the PM2.5 levels inside a room and outdoor was
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simultaneously measured by a real time aerosol monitor. It was found that under high
ventilation conditions the indoor air quality significantly correlates with outdoor air quality
while under low ventilation conditions indoor air weakly correlates with outdoor air. The 24-
hour mean value of PM2.5 was logged to be 172.45µg/m3 indoors while it was merely
108.26µg/m3 outdoors. The higher indoor levels might be because of the presence of a smoker
in the room .The results shows the more the ventilation more will be correlation with outdoor
air while low ventilation leads to the definition of indoor air quality majorly by indoor sources
rather than outdoor sources.
The role of these factors was examined by Ali et al. (2015a) during a study in a
residential built environment where the mass concentration of PM1, PM2.5 and PM10 were
measured for 24 hours in the kitchen and living room simultaneously by means of two
DustTrak aerosol monitor (model 8520, TSI Inc. Higher concentration of PM was monitored
in kitchen and living rooms during the winter season than in summers along with high
background concentration during winter. The study results illustrate that increased ventilation
in summer reasons decreases mass concentration of particulate matter. The infiltration from
outdoor sources was found to be one the reason for higher mass concentration of coarse fraction
of particulate matter in the living room as compared to the kitchen.
The entire region of Pakistan is pretentious by air pollution. Recently Zainab et al.
(2015) observed differential behavior of particulate with varying altitude. Using a real time
aerosol monitor, DustTrak DRX (model 8533, TSI Inc.) the PM fractions were monitored at
two sites of China and Pakistan at elevations above 3000m for 24 hours. The average
concentration of PM was higher in Pakistan at elevation above 3000m as compared to China
while both having higher PM mass concentration than the recommended levels of 25 µg/m3 by
Chapter Two Literature Review
60
WHO. The results suggest risk exposure to PM even at places distant from anthropogenic
sources.
Zona et al. (2015) monitored particulate levels at different altitudes of Pakistan.
Various factors affected air quality at each monitored site. High elevation exhibited higher
particulate levels while lowest 24-h average was observed at sea level. Anthropogenic
activities were noted to a contributing factor.
The dispersion of particulate matter is more pronounced at high temperature in
summers as compared to the low temperature in winter. To assess the seasonal impact on the
PM (Ali et al., 2015b) selected a high altitude tourist resort in Pakistan. The PM concentration
was measured for 24 hours during summer and winter season using DustTrak DRX (Model
8533, TSI Inc. while the meteorological properties were stated using Kestrel 4500 Pocket
Weather Tracker (Nielsen- Kellerman). Highest concentration was noted during summers
when the temperature was high along with high wind speed. The study testifies the bulbous
effect of seasonal shift on the average levels of particulate matter.
While discussing health in various imperative sectors, educational sector cannot be
ignored. Pakistan being a developing country is fronting serious health and environmental
issues. The air quality in the educational sector has not been comprehensively considered in
the educational built environment. To provide with the base line data on air quality in this
environment Aziz et al. (2015a) designed a study to assess the correlation of indoor air with
and ambient air and the possible sources of PM determining indoor air quality. Using a
DustTrak Aerosol Monitor (TSI Model 8520) the levels of PM2.5 in the indoor (class rooms)
and ambient air in the University of Punjab were monitored for 24 hours. The class rooms were
selected on the base of occupant density and were alienated as low, medium and high
Chapter Two Literature Review
61
occupancy rooms. The ventilation rate was also measured to find out the correlation of indoor
air with ambient air. According to the results of this study the occupant density and the ambient
air effectively controls the PM levels in the indoor and hence affecting air quality.
Particulate matter has been found as one of the serious threat to the patients and health
care staff in the hospitals. The long term exposure of the patients and the health care staff to
the increase levels of particulate matter in the hospitals can be source of potential damage to
their health. It can, therefore, be used as a tool in determining the air quality of the wards and
operating suites in the hospitals. Nimra et al. (2015) monitored the average levels of particulate
matter for 24 hours in the operation theatres and ambient air of two hospitals of Lahore by
using DustTrak Aerosol Monitor (TSI Model 8520) and DRX Aerosol Monitor (TSI Model
8533). Highest levels of particulate matter were observed in the operation theatres with natural
ventilation while the lowest particulate matter concentration was reported in a theater that was
equipped with vertical Laminar flow system. The major PM contributor was found to be the
human traffic inside the theatre and door opening/closing rate along with the building age.
Similarly, a study was conducted by Gulshan et al. (2015) in the five wards (medical,
pulmonology, surgical, paediatric and nephrology) of Sheikh Zayed hospital of Lahore
Pakistan to assess the indoor and ambient air quality. Two DRX Aerosol Monitors (TSI Model
8533) were installed in parallel to determine the PM levels inside the ward and in the ambient
air for 24 hours. High levels of particulate matter were observed inside the wards excluding
surgical and paediatric ward as compared to outdoor PM levels which shows poor ventilation
and poor health status in Pakistan.
The ever increasing vehicular load on the roads has created a threatening situation for
the survival of human beings on earth. The PM burden created by vehicular exhaust on two
Chapter Two Literature Review
62
busy roads (Campus Bridge-Punjab University and Thokar Niaz Baig) of Lahore Pakistan has
been reported by Ali et al. (2015c). DustTrak DRX (Model 8533, TSI Inc.) was used to monitor
the particulate matter concentration for 24 hours while BW gas probe was used to screen
temperature and humidity levels .According to their finding the meteorological properties and
the vehicular load positively correlates with intensification of PM. It is a need of time to pay
attention on the transport industry to control urban pollution.
With the growth in the transport industry in the developed as well as developing
countries there is a need to evaluate the increase risk pose by the intensification of this sector.
The transport micro environments are of vital importance as these are susceptible to increase
levels of PM, CO, CO2 due to infiltration form road side, traveler’s activities and most owed
vehicular exhaust pollution. To scrutinize the air quality status in these microenvironments
Aziz et al. (2015b) conducted a study in which the mass concentration of PM was measured
along with CO2, CO, temperature and humidity in the diesel power-driven buses in United
Kingdom and Pakistan. The exposure to the PM by the commuters on inter-city journeys was
monitored using DustTrak DRX (Model 8533, TSI Inc.). The observed levels of PM were not
in accordance to the WHO guidelines in both countries. While comparing the vehicular load
and vehicular exhaust emissions in both countries, Pakistan seems to have more intimidating
situation at present by having higher concentration of PM as compared to United Kingdom.
The increasing industrialization, urbanization and subsequent traffic load in the
developing countries is one of the major concerns. Exposure to the particulate matter is of
vigorous importance when the air pollution hazards are being discussed as it reasons
pulmonary obstructive diseases. A study was conducted by Nasir et al. (2015) to assess the
exposure to particulate matter due to automobiles at two different road sites in Lahore,
Chapter Two Literature Review
63
Pakistan. The mass concentration and number concentration of PM was stated by using
GRIMM analyzers (Model 1.101 and Model 1.108) and condensation particle counter (TSI
3781) during week days and were compared with the observed concentration during weekends.
The detected concentration was also compared with a background site. The heavy metals (Al,
Si, Cu, Zn, Mn, Cd, Ni and Pb) were also reported by using Graphite Furnace Atomic
Absorption Spectrophotometer (Unicam atomic absorption, Cambridge, UK). The acquired
results indicated that the mass and number concentrations were higher at road site as compared
to the background site along with higher meditation during week days as compared to
weekends. Among the heavy metals Mn, Ni and Cd were found to be exceeding WHO limits.
The growing urban sector needs to pay special attention on the air pollution scenario in time.
The heavy metal analysis of particulate matter leads to better understanding of the
chemical nature of this pollutant. In Pakistan the heavy metals in the indoor and outdoor
particulate matter and dust at two rural and one urban residential built environment were
analyzed by Nasir et al. (2015d). To collect the air borne PM an eight stage non-viable
impactor (Thermo Fisher Scientific Inc., USA) laden with EMP 2000 glass microfiber filter
papers (Whatman, England) was cast-off. The settled dust from the indoor surfaces was
collected from floors, cupboard in living rooms and kitchens at the rural sites while the
courtyards dust was used as outdoor dust samples. In urban zone the dust samples were also
collected from 27 diverse locations in the outskirts of Lahore along with University of
Veterinary and Animal Sciences as a background site. The cake dungs from a rural site were
also collected because of its usage as a fuel in rural areas. Graphite Furnace Atomic Absorption
Spectrophotometer was used for heavy metal analysis including Si, Al, Zn, Mn, Cu, Ni, Cd,
Pb, Co and As. Higher concentration of heavy metals were observed in the indoor
Chapter Two Literature Review
64
environments except Cu, Si and Pb at rural site 1. Similarly higher heavy metal concentration
were monitored in the outdoor air at rural site 2 except for Ni whose levels were considerably
higher in the indoor than out door. Uppermost heavy metal levels were monitored at urban site
having rich levels in the outdoor air. The heavy metal concentration of Pb was found to be
within the recommendation value of WHO (0.5 μg/m3) but the levels of Ni, Mn and Cd were
greater at all sites than WHO and European commission recommended values emphasizing
health hazards risk by the heavy metals exposure.
As evident from the above mentioned researches, there is a pressing need for more
detailed and repeated measurements of air quality in Pakistan. It is an established fact that
biomass burning is a significant contributor towards higher particulate matter. However, the
sources of particulate matter and the source strength need to be highlighted in urban areas as
well. While rural areas have been monitored for pollutant levels, indoor environments of urban
areas have not yet been monitored so far leading to the formulation of this study.
Chapter Three Materials and Methods
65
CHAPTER THREE
MATERIALS AND METHODS
Study Area
The historical city of Lahore (31°15′—31°45′ N and 74°01′—74°39′ E) is the
provincial capital of Punjab and the second largest city of Pakistan. River Ravi flows along the
north-western side of the city. This city is spread over an area of 1772 km2 at an elevation of
217m above the sea level (Figure 4). In 2001, Lahore was assigned the administrative status of
City District and is divided into nine administrative towns and a cantonment area (under
military administration).
Figure 4: Map marking the boundaries of City District Lahore
Chapter Three Materials and Methods
66
Being one of the densely populated cities of the world, the population of Lahore is
around 9,086,000 inhabitants (BOS, 2013).
The city district experiences a hot, semi-arid climate with an average temperature of
24.3oC (75.7oF) (Rasheed et al., 2015). During the extremely hot summers, the maximum
average temperature ranges between 33 to 39oC with minimum average temperature falling
between 22 to 28oC. The winters experience an average maximum temperature of 17-22oC and
the minimum temperature ranging between 7 to 12oC (Alam et al., 2012). The city receives an
annual rainfall of between 600 to 800 mm, most of it occurring during the monsoon period
(from Mid-July till September). Annually the city receives an average of 3,094 hours of
sunshine. The day length is also variable with the shortest day being December 21 with 10:05
hours of daylight and 20th June being the longest day with 14:12 hours of daylight (Pakistan
Meteorology Department).
The inhabitants of Lahore enjoy five seasons in a year namely winter, spring, summer,
monsoon, autumn and winter (Köppen climate classification BSh):
Winter season with January being the coolest month (beginning from 15th November
till 15th February)
Spring season which is generally pleasant from16th February to 15th April
Hot summer season starting from mid-April till June which is the hottest month of the
year
Rainy season or Monsoon which begins in July and lasts till September
Dry autumn (16th September-14th November)
Chapter Three Materials and Methods
67
Selection of sampling sites
The Lahore Cantonment is a legal settlement within the city under military
administration while the rest of the City District Lahore is divided into nine administrative
towns with their details given in table 3 below:
Table 3: Administrative towns of City District Lahore and their population (Source: GOP,
2014)
Administrative town Total number of
Union Councils
Area (km2) Population as
estimated on 31-12-
2014
Aziz Bhatti Town 11 69 610000
Data Ganj Buksh Town 18 33 1048000
Gulberg Town 15 44 841000
Iqbal Town 15 520 835000
Nishtar Town 19 497 1081000
Ravi Town 30 38 1713000
Samanabad Town 19 38 1064000
Shalimar Town 11 24 573000
Wagha Town 12 440 709000
Cantonment - 98 874000
Thirty houses were selected from all over Lahore to serve as sampling sites for
monitoring of indoor air quality in terms of fine particulate matter and bio-aerosols. In order
to ensure a random mix of houses, sampling sites of varying floor area were selected from each
town. Three categories were defined according to the size of the houses with following details.
Small: < 126.5 m2
Chapter Three Materials and Methods
68
Medium: > 126.5 m2 to 253 m2
Large: > 253 m2
Since the selection of the houses was random, therefore the surroundings of the houses
varied considerably with some houses located in industrial areas, some in semi-urban areas
while some were located in urban areas. This variation was also useful to provide an insight
into the impact of surroundings on the indoor air quality of the sampling sites. Moreover it was
helpful in providing with a more generalized overview of air quality of indoor environments.
All the selected houses were located within 1 km radius from main roads with variable traffic
throughout the day.
Since the number of people and their activities are also an important contributor
towards indoor air quality, three levels of occupancy were also defined as follows:
Low: <5 occupants
Medium: 6-10 occupants
High: >10 occupants
However this classification was not the basis of selection of houses and was used in
describing the results. In order to collect the results following steps were carried out at each
sampling site:
Filling of questionnaire
A questionnaire was filled for each sampling site to gain information about the number
of occupants, their daily activities, occupations, time spent indoors and outdoors by each
Chapter Three Materials and Methods
69
member of the household, smoking habits, type of cooking fuel, their health status, and other
related factors. The data thus obtained was useful in providing with an insight into the daily
routine of the occupants and the possible exposures to pollutants at home and outside as well.
The questionnaire is attached as Annexure-I.
Sampling for PM2.5 at the selected study sites
There are numerous methods for particulate sampling and two of the most widely used
methods employed for PM monitoring are the light scattering method and gravimetric method.
Although gravimetric method is more suitable as a reference method, light scattering method
is more suitable for preliminary measurents of aerosols (Niu et al., 2002). Among the many
commercially available photometers, DustTrak aerosol monitor (model 8520, TSI Inc.) has
been known to give more precise and accurate readings of PM2.5 (Yanosky et al., 2002; Cheng,
2008) and was employed to monitor PM2.5 concnetrations in this study.
DustTrak aerosol monitor (model 8520, TSI Inc.) is a direct reading real-time
photometer and has a laser diode with 90° light scattering. Its sensitivity ranges between 0.001
to 100 mg/m3 with a particle size range of 0.1 to approximate 10 μm. The monitor is factory
calibrated to the respirable fraction of standard ISO 12103-1, A1 test dust. The aerosol
monitors were factory calibrated before monitoring and the air flow rate was set at 1.7 L/min.
The aerosol monitor has separate inlet nozzles for measurement of PM1, PM2.5, and PM10.
Since fine particulate matter is a major component of the indoor air (Geller et al., 2002),
therefore this size fraction was selected for monitoring in the indoor micro-environments. Data
logging interval was set at 1 minute and the sampling duration was 72 hours in each house.
Before running the instrument at any sampling site, the inlet nozzles were cleaned and
lubricated each time according to the prescribed protocl given in the instuction manual of the
Chapter Three Materials and Methods
70
equipment. The aerosol monitor is powered by electricity and as an alternative power supply
Cameleon C-size rechargable batteries were used.
Two different micro-environments i.e. kitchen and living room were selected for
sampling within the houses and two DustTrak monitors were run in parallel in the both micro-
environments. The instruments were placed at a height of approximately one meter from the
ground. Care was taken while performing daily routine activties and no major activty was
allowed too near the instrument which could otherwise cause a sudden increase in PM2.5 levels.
The data was later on transferred to a computer using the TrakPro software for further analysis.
The monitoring began in January 2012 and continued till March 2013 with each sampling site
monitored only once. The monitoring was conducted only once at each selected sampling sites
as the instruments were somewhat noisy and many residents were being disturbed by their
presence. This factor was a significant limitation in this study.
PM2.5 generation from different activities
Different household activities were considered to be a cause of variation in
concentrations of particulate matter within a house. The source strengths of particulate matter
arising from different activities being carried out in each sampling site were determined by
identifying the time period during which a specific activity was being performed and
calculating the average levels of PM2.5 during that time. The major activities identified
included cooking, cleaning, material movement such as making bed and shifting of items,
presence of people, space heating during winters and cigarette smoking. In Pakistan, cooking
involves heavy frying paricularly during breakfast preparation so cooking activity was further
divided into two categories: Cooking including extensive frying (during breakfast), and
Cooking with little or no frying (during lunch and dinner). Cleaning activty included both floor
Chapter Three Materials and Methods
71
sweeping and dusting of surfaces etc. Gas heaters were employed during the winter season for
space heating and PM levels during the usage period were also isolated to determine its impact
on indoor air quality.
Sampling of bio-aerosols at the selected study sites
Gravitational method (Koch sedimentation) was employed for sampling of air-borne
bacteria and fungi in the kitchens and living rooms of the sampling locations. This type of
sampling involves exposure of agar coated surfaces, usually petri plates, for a specific time
period to allow settling of air-borne microorganisms upon the agar medium. The plates are
later incubated to allow growth of microorganisms and the microbial species identified.
Although it is a passive sampling method which does not allow exact quantitative analysis,
data collected by sedimentation method allows the drawing of correct conclusions on types of
microorganisms present in the air and can give a rough approximation of bacterial and fungal
concentration (Stryjakowska-Sekulska et al., 2007). There are relatively few studies which
have employed passive sampling for bioaerosol sampling and the exposure time also varies
between 5 minutes (Afzal et al., 2004), 15 minutes (Stryjakowska-Sekulska et al., 2007) and
30 minutes (Bogomolova and Kirtsideli, 2009).
The medium used for bacterial sampling was Tryptic Soy Agar (TSA) while Malt
Extrose Agar (MEA) was used for fungal sampling. For MEA preparation, the media
containing malt extract and agar having a pH of 6 was sterilized by autoclaving at 121+1°C
for 15 minutes. It was cooled down and antibacterial was added to avoid bacterial
contamination. It was poured in sterilized petri plates in laminar air flow chamber and left for
24 hours at 25+1°C. For preparing TSA medium, 40 g of the medium was suspended in one
liter of purified water. It was heated with frequent agitation and boiled for one minute to
Chapter Three Materials and Methods
72
completely dissolve the medium. Then it was autoclaved at 121°C for 15 minutes. After
pouring in sterilized petri plates in laminar flow chamber, it was left to solidify overnight at
25+1°C (Cappuccino and Sherman, 2005).
Settle plates containing TSA and MEA agar medium were exposed for twenty minutes
each in both rooms to allow the bio-aerosols (bacteria and fungi) to settle on the agar coated
surface. Temperature and humidity of the two rooms was also noted at the time of exposure.
The Petri plates were then incubated at 27oC for three days to allow growth of settled viable
bioaerosols on the growth medium. The number of colonies formed on the agar medium was
counted and the colony forming units per meter cube was determined using the Omelyansky
formula as followed by (Bogomolova and Kirtsideli, 2009).
N = 5a.104 / (b.t)
Where:
N = colony forming units per m3 (cfu/m3)
a = no. of colonies per Petri dish
b = surface area of dish (cm2)
t = exposure time (minutes)
The plates were observed under a microscope to observe the morphological
characteristics of the colonies such as shape, colour, and margin. Identification was carried out
by following Bergey’s Manual of Systematic Bacteriology and a fungal identification key by
Dugan (2005).
Chapter Three Materials and Methods
73
Measurement of Air Change rate per Hour (ACH)
All the sampling sites in this study were naturally ventilated. Fans and occasionally air
conditioners were switched on during the warmer months. Air change per hour was measured
to determine the amount of ventilation available at each site. Concentration decay method was
employed using CO2 as the tracer gas. A fire extinguisher cylinder filled with carbon dioxide
gas was the source of CO2 while Gas Probe IAQ (BW technologies) was employed for
measuring the concentrations of gas. Ventilation was measured in both the kitchen and living
room of each sampling site. The procedure was commenced in the absence of people in the
room so that CO2 levels were not affected. The background level of carbon dioxide was noted
prior to releasing the gas into the room. The gas was injected into the room until the levels
were four times the background levels; the levels were then monitored as they decreased over
time. The monitoring continued until background levels were achieved. Ventilation was
determined by plotting the time in hours against the natural log of CO2 concentration where
ACH was the slope of the line of best fit (Fischer-Mackey, 2010). The step wise procedure is
stated below:
The background concentration of CO2 was noted.
CO2 gas was injected into the room and allowed to mix evenly in the room with the
help of fans.
The concentration of gas was noted after every five minutes until the concentration was
within 200 ppm of the baseline value.
Natural log of CO2 (ppm) was plotted over time (hours) where ACH = slope of the line
of best fit.
Chapter Three Materials and Methods
74
The volume of a room is also an important configuring factor for indoor air quality.
The volume of air entering the specified rooms was also determined by employing the simple
formula given below:
Ventilation rate (L/sec) = ACH x Volume of room (m3)
3.6
Natural ventilation does not ensure a uniform mixing and availability of fresh air at all
times. Therefore, the volume of air present per person in both micro-environments was also
calculated as follows:
Ventilation rate (L/s/person) = L/sec x number of people in the room
Data analysis
The obtained concentrations of PM2.5 for 72 hours were converted into 24-h average
concentrations. Representative PM2.5 averages for 24-hours were plotted against time to
observe the daily trend in PM levels throughout the day. The data were analyzed further to
obtain hourly maximum and hourly minimum statistics to gain an insight into the fluctuations
in levels during the sampling duration and for comparison with the background levels.
Variation of PM levels during the day and night hours also holds a significance in a daily cycle.
Since the monitoring was conducted during different times throughout the year, the length of
day and night for each monitoring period was obtained from the meteorology department.
Subsequently, diurnal variations were also compared for each sampling site. Similarly data
from kitchen and living room was plotted to observe the influence of connection between the
two rooms upon particulate matter levels.
Since a household carries on a variety of activities throughout the day, generation of
PM levels from major activities in the selected sampling sites were also noted. Activities
resulting in highest PM generation were also documented.
Chapter Three Materials and Methods
75
Seasonal variation was studied by comparing the mean concentrations of particulate
matter in each sampling site during the different seasons. One-Way ANOVA was applied to
observe any significant impact of seasons on particulate matter concentrations (α = 0.05).
Correlation between air exchange rate and PM concentrations was calculated to study the role
of ventilation rates in defining the PM2.5 levels in the indoor air.
Regression analysis was carried out to observe the association of various variables
(temperature, relative humidity, ventilation, PM2.5) with bioaerosol levels. Seasonal variation
was also checked through One-Way ANOVA. SPSS (v.16.0) was employed for statistical
analysis.
Chapter Four Results
76
CHAPTER FOUR
RESULTS
The selected sites (n = 30) were located within a distance of 1 km from heavy traffic
roads with a variety of urban habitat surroundings. Among the ten selected houses located
in industrial areas, two were present in semi urban areas and two were present near railway
lines (Figure 5).
Figure 5: Location of sampling sites in Lahore city
None of the buildings was air tight, rather all were naturally ventilated. Since the
climate of Lahore is warm during most time of the year, windows were generally kept open
except during the winters. Gas heaters were in common use for space heating during the
winters while mostly ceiling fans were used for cooling for the rest part of the year with air
conditioners also used during the hotter months. The number of occupants varied from three
to thirteen at the selected sites (Figure 6).
Chapter Four Results
77
Figure 6: Location of sampling sites according to number of occupants [up to 5 occupants
(red circles); 6 to 10 occupants (blue circles); 11 and above (green circles)]
Natural gas was used as the primary cooking fuel with LPG also used in only two
houses. However it was not used much often. The kitchen and living room were not
connected in nineteen houses, partially connected in six and fully connected in remaining
five houses (Table 4).
Chapter Four Results
78
In most of the houses, majority of occupants were students, house wives and job
workers. The proportion of males and females falling in the various age groups is shown in
figure 7.
Figure 7: Proportion of male and female occupants belonging to different age groups
Time spent by each member in the house varied from less than eight hours to full
day. Mostly females and elderly people spent full day at home while males and students
spending more time outdoors (Figure 8 and 9).
0-10 YEARS 11-20 YEARS 21-30 YEARS 31-40 YEARS 41-50 YEARS 51-60 YEARS61-
ONWARDS
MALES 9 22 26 5 13 10 6
FEMALES 12 31 34 9 15 5 5
0
5
10
15
20
25
30
35
40
Chapter Four Results
79
Figure 8a: Number of hours spent by male occupants in the house
Figure 8b: Number of hours spent by female occupants in the house
7%
73%
20%
0-8 HOURS 9-16 HOURS 17-24 HOURS
0%
38%
62%
0-8 HOURS 9-16 HOURS 17-24 HOURS
Chapter Four Results
80
Figure 9: Time spent by females in the kitchen
0-4 HOURS57%
5-8 HOURS37%
9-12 HOURS6%
Chapter Four Results
81
Trends in PM2.5 levels in microenvironments of Category-A sampling sites
Sampling sites of category-A had a floor area ranging from 75.9 m2 to 126.5 m2. The
number of occupants varied from 4 to 13 occupants among whom two were frequent smokers.
The selected sites were monitored during different seasons with A1 and A10 monitored during
the winter season, A2 and A3 during the spring season, A4 and A5 during the summers, A6
and A7 in monsoon or rainy period and A8 and A9 monitored during the dry autumn. All the
selected sites were located within a radius of 1 Km from main roads with cemented or carpeted
adjacent roads in most cases while the roads outside two sites were unpaved dust roads. The
location of the houses varied considerably with six sites present in industrial areas while one
of them was in semi-urban surroundings. Table 4 provides with an overview of each of the
sampling sites.
Floor plans of each site were prepared to assess the spaces present for air exchange as
well as connection between the two microenvironments. It was noted that no direct connection
existed between the kitchens and living rooms in any of the houses while in three of the houses,
doors of both rooms opened into the same room (partially connected). The dimensions of the
doors and windows along with the rooms where monitoring was conducted are also in the floor
plans (figure 10, 12, 14, 16, 18, 20, 22, 24, 26, and 28).
Since PM2.5 monitoring was carried out for seventy two hours in each house, trends of
PM2.5 were plotted for representative twenty four hours average in both the kitchens and living
rooms. Major activities and the time during which they were performed were identified and
pointed out in a 24-hour period along with PM2.5 levels in each sampling site as shown in figure
11a, 11b, 13a, 13b, 15a, 15b, 17a, 17b, 19a, 19b, 21a, 21b, 23a, 23b, 25a, 25b, 27a, 27b, 29a,
Chapter Four Results
82
and 29b. The 24-hours, hourly maximum and minimum average levels for PM2.5 were
calculated and tabulated in table 5. This data was helpful in comparing the mean and maximum
PM2.5 levels with the background levels (average of hourly minimum) in each house.
The air exchange rate was calculated for both kitchen and living room; once with open
doors and windows to obtain maximum air exchange rate and then with closed doors and
windows to obtain minimum air exchange rates (Annexure-II).
Chapter Four Results
83
Table 4: Profile of Category-A sampling sites
Sampling
site
Size of
house
(m²)
Occupants Location Type of road Distance from
main road
Connection between
kitchen and living
room
Cooking
fuel
No. of
smokers
A 1 126.5 6 Urban, Industrial Tiled 0.2 km Not connected NG 0
A 2 126.5 7 Urban Carpeted 1 km Not connected NG 1
A 3 75.9 7 Urban Cemented 0.2 km Partially connected NG 0
A 4 126.5 8 Urban Cemented 0.5 km Not connected NG 0
A 5 50.6 12 Urban, near railway lines Cemented 0 km Not connected NG 11
A 6 126.5 6 Industrial, near railway lines Carpeted 0.1 km Not connected NG 0
A 7 75.9 7 Semi-urban, Industrial Unpaved 1 km Partially connected NG 0
A 8 63.25 6 Urban, Industrial Cemented 1 km Not connected NG 0
A 9 126.5 13 Urban, Industrial, Main Road under
construction
Cemented 0.1 km Not connected NG 0
A 10 101.2 4 Urban, Industrial Unpaved 0.1 km Partially connected NG 0
1 Smoking carried indoors
Chapter Four Results
84
Table 5: Representative 24-h, hourly maximum and hourly minimum averages of PM2.5 recorded in the kitchens and living rooms
of category-A sites
Sampling
site
PM2.5 IN KITCHEN (µg/m³)
24 HOURS HOURLY MAXIMUM HOURLY MINIMUM
Average Max Min St dev Average Max Min St dev Average Max Min St dev
A1 224.5 236.5 207.0 15.5 529.0 746.7 396.3 190.0 60.2 74.9 51.6 12.8
A2 188.8 200.6 168.2 17.9 336.4 396.1 289.1 54.5 75.4 91.0 63.8 14.0
A3 185.3 206.3 164.9 20.7 1118.5 2355.8 492.2 1071.5 48.9 57.3 36.1 11.3
A4 69.9 92.4 56.1 19.7 206.9 399.1 81.2 169.1 34.0 38.7 24.9 7.9
A5 132.9 169.8 89.1 40.8 369.5 405.0 306.6 54.6 48.6 77.4 26.05 26.2
A6 202.3 296.4 131.8 84.8 1787.4 3666.4 233.8 1739.3 53.4 66.1 29.2 20.9
A7 342.7 437.7 289.4 82.4 1044.2 1443.1 605.0 420.5 135.6 193.4 101.1 50.3
A8 191.8 248.1 136.7 55.7 565.5 749.0 342.2 206.3 84.7 97.6 71.1 13.3
A9 422.7 576.2 259.4 158.7 1256.6 1817.7 847.1 502.5 86.2 129.9 64.1 37.8
A10 456.7 488.8 409.8 41.5 1697.2 2639.4 1208.5 816.1 153.6 212.4 99.7 56.5
PM2.5 IN LIVING ROOM (µg/m³)
A1 139.7 149.7 126.9 11.6 283.1 319.8 245.4 37.2 48.4 55.6 44.8 6.1
A2 149.0 168.4 123.1 23.3 265.3 309.1 239.5 38.2 69.0 89.8 57.9 17.9
A3 168.4 181.4 157.7 12.0 866.3 1774.5 380.1 787.2 46.2 56.6 29.2 14.8
A4 119.9 127.4 113.9 7,0 231.2 281.8 173.3 54.6 66.7 73.1 58.8 7.2
A5 177.2 234.3 125.4 54.7 437.9 591.3 356.1 133.0 69.2 126.7 26.9 51.6
A6 123.4 140.2 109.7 15.5 231.3 295.4 187.0 56.8 54.7 71.4 29.7 22.0
A7 336.3 433.7 287.4 84.3 857.2 1064.9 489.2 319.6 148.2 200.0 114.3 45.6
A8 179.7 253.2 142.7 63.6 398.0 801.4 194.8 349.3 99.7 118.6 81.5 18.6
A9 509.3 660.4 419.5 131.7 1671.5 2626.2 1065.1 836.8 75.4 76.4 74.9 0.8
A10 383.2 433.3 290.6 80.3 874.8 1077.8 745.0 178.1 187.9 235.7 117.9 61.9
Chapter Four Results
85
Sampling site A1
Figure 10: Floor plan of sampling site A12
Figure 11a: 24-h representative mean values of PM2.5 in kitchen of sampling site A1
2 K stands for kitchen, LR for living room, and B1, B2 etc. are the bedrooms. The blue bars represent the windows
while the pink bars represent the doors. The rooms in pink are the sampling sites, blue colour represents the porch
or courtyard while green colour represents grassy lawns.
0
100
200
300
400
500
600
700
800
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
Cleaning Cooking
Chapter Four Results
86
Figure 11b: 24-h representative mean values of PM2.5 in living room of sampling site A1
0
50
100
150
200
250
300
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
er…
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cleaning
Movement of people
Chapter Four Results
87
Sampling site A2
Figure 12: Floor plan of sampling site A2
Figure 13a: 24-h representative mean values of PM2.5 in kitchen of sampling site A2
0
50
100
150
200
250
300
350
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
Cleaning
Unidentified
Chapter Four Results
88
Figure 13b: 24-h representative mean values of PM2.5 in living room of sampling site A2
0
50
100
150
200
250
300
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cleaning
Movement of people
Unidentified
Chapter Four Results
89
Sampling site A3
Figure 14: Floor plan of sampling site A3
Figure 15a: 24-h representative mean values of PM2.5 in kitchen of sampling site A3
0
500
1000
1500
2000
2500
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
90
Figure 15b: 24-h representative mean values of PM2.5 in living room of sampling site A3
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Infiltration from kitchen
during cooking
Movement of
peopleCleaning
Chapter Four Results
91
Sampling site A4
Figure 16: Floor plan of sampling site A4
Figure 17a: 24-h representative mean values of PM2.5 in kitchen of sampling site A4
0
20
40
60
80
100
120
140
160
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
er…
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking activity at random
times according to varying
occupants’ schedules
Cleaning
Chapter Four Results
92
Figure 17b: 24-h representative mean values of PM2.5 in living room of sampling site A4
0
50
100
150
200
250
300
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
er…
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Movement of
people
Cleaning
Chapter Four Results
93
Sampling site A5
Figure 18: Floor plan of sampling site A5
Figure 19a: 24-h representative mean values of PM2.5 in kitchen of sampling site A5
0
50
100
150
200
250
300
350
400
450
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
94
Figure 19b: 24-h representative mean values of PM2.5 in living room of sampling site A5
0
100
200
300
400
500
600
700
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Smoking indoors
Cleaning
Chapter Four Results
95
Sampling site A6
Figure 20: Floor plan of sampling site A6
Figure 21a: 24-h representative mean values of PM2.5 in kitchen of sampling site A6 (monitored
during Ramadan)
0
500
1000
1500
2000
2500
3000
3500
4000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
Chapter Four Results
96
Figure 21b: 24-h representative mean values of PM2.5 in living room of sampling site A6
0
20
40
60
80
100
120
140
160
180
200
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cleaning
Movement
of people
Movement of
people
Chapter Four Results
97
Sampling site A7
Figure 22: Floor plan of sampling site A7
Figure 23a: 24-h representative mean values of PM2.5 in kitchen of sampling site A7
0
100
200
300
400
500
600
700
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cleaning
CookingUnidentified
Chapter Four Results
98
Figure 23b: 24-h representative mean values of PM2.5 in living room of sampling site A7
0
100
200
300
400
500
600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
concn
etra
tio
ns
(µg/m
³)
Hours
Movement of
people
Cleaning
Unidentified
source
Chapter Four Results
99
Sampling site A8
Figure 24: Floor plan of sampling site A8
Figure 25a: 24-h representative mean values of PM2.5 in kitchen of sampling site A8
0
100
200
300
400
500
600
700
800
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
100
Figure 25b: 24-h representative mean values of PM2.5 in living room of sampling site A8
0
100
200
300
400
500
600
700
800
900
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Due to no exhaust and window in the
kitchen, activties in the kitchen
influencing the levels in living room
Cleaning
Chapter Four Results
101
Sampling site A9
Figure 26: Floor plan of sampling site A9
Figure 27a: 24-h representative mean values of PM2.5 in kitchen of sampling site A9
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
CookingUnidentified
Chapter Four Results
102
Figure 27b: 24-h representative mean values of PM2.5 in living room of sampling site A9
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Movement of people
Cleaning
Unidentified source
Chapter Four Results
103
Sampling site A10
Figure 28: Floor plan of sampling site A10
Figure 29a: 24-h representative mean values of PM2.5 in kitchen of sampling site A10
0
500
1000
1500
2000
2500
3000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
er…
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
Chapter Four Results
104
Figure 29b: 24-h representative mean values of PM2.5 in living room of sampling site A10
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Movement of people
+ infiltration from
semi-open kitchen
Chapter Four Results
105
Trends in PM2.5 levels in microenvironments of Category B sampling sites
Sampling sites of category B had a floor area ranging from 177.1 m2 to 253 m2. The
number of occupants varied from 3 to 13 occupants among whom five were frequent smokers.
However smoking was carried out within houses in only two cases. The selected sites were
monitored during different seasons with B1, B2, B8 and B9 monitored during the winter
season, B3, B4 and B10 during the spring season, B5 during the summers, B6 in monsoon or
rainy period and B7 monitored during the dry autumn. All the selected sites were located within
a radius of 1 Km from main roads with cemented or carpeted adjacent roads in most cases
while the road outside one site was unpaved dust road. The location of the houses varied
considerably with two sites present in industrial areas while one of them was in semi-urban
surroundings. Table 6 provides with an overview of each of the sampling sites.
Floor plans of each site were prepared to assess the spaces present for air exchange as
well as connection between the two microenvironments. It was noted that a direct connection
existed between the kitchens and living rooms in three houses while in rest of the cases, both
rooms were located far apart. The dimensions of the doors and windows along with the rooms
where monitoring was conducted are also given in the floor plans (figure 30, 32, 34, 36, 38,
40, 42, 44, 46, and 48).
Since PM2.5 monitoring was carried out for seventy two hours in each house, trends of
PM2.5 were plotted for representative twenty four hours average in both the kitchens and living
rooms. Major activities and the time during which they were performed were identified and
pointed out in a 24-hour period along with PM2.5 levels in each sampling site as shown in figure
31a, 31b, 33a, 33b, 35a, 35b, 37a, 37b, 39a, 39b, 41a, 41b, 43a, 43b, 45a, 45b, 47a, 47b, 49a,
Chapter Four Results
106
and 49b. The 24-hours, hourly maximum and minimum average levels for PM2.5 were
calculated and tabulated in table 7. This data was helpful in comparing the mean and maximum
PM2.5 levels with the background levels (average of hourly minimum) in each house.
The air exchange rate was calculated for both kitchen and living room; once with open
doors and windows to obtain maximum air exchange rate and then with closed doors and
windows to obtain minimum air exchange rates (Annexure-II).
Chapter Four Results
107
Table 6: Profile of Category-B sampling sites
Study
site
Size of
house
(m²)
Occupants Location Type of
road
Distance from
main road
Connection between
kitchen and living
room
Cooking
fuel
No. of
smokers
B 1 253 12 Urban, Industrial Tiled 0.2 km Not connected NG 0
B 2 177.1 4 Urban Carpeted 0.1 km Fully Connected NG 0
B 3 253 6 Urban Carpeted 0.1 km Not connected NG 0
B 4 253 3 Urban Carpeted 0.1 km Not connected NG 0
B 5 202.4 7 Industrial, near railway lines Cemented 0.1 km Not connected NG 1
B 6 253 8 Urban Carpeted 0.1 km Not connected NG 0
B 7 177.1 4 Urban Carpeted 0.5 km Fully Connected LPG 0
B 8 151.8 6 Semi-urban Unpaved 1 km Fully Connected NG 13
B 9 177.1 13 Urban Carpeted 0.5 km Not connected NG 2
B 10 177.1 6 Urban Carpeted 0.7 km Not connected NG 13
3 Smoking carried indoors
Chapter Four Results
108
Table 7: Representative 24-h, hourly maximum and hourly minimum averages of PM2.5 recorded in the kitchens and living rooms
of category-B sites
Study
site
PM2.5 IN KITCHEN (µg/m³)
24 HOURS HOURLY MAXIMUM HOURLY MINIMUM
Average Max Min St dev Average Max Min St dev Average Max Min St dev
B1 983.0 1259.5 692.4 283.9 5068.1 9597.4 1685.6 4078.6 172.1 200.3 153.0 24.9
B2 236.7 298.5 165.0 67.3 760.9 1333.8 368.7 507.3 107.9 150.4 59.0 46.0
B3 445.6 681.5 237.5 223.3 1588.5 3383.4 542.3 1561.5 126.9 150.6 80.6 40.1
B4 185.3 222.8 143.4 39.9 470.8 516.5 381.5 77.4 58.2 104.8 34.1 40.3
B5 250.5 368.5 162.2 106.3 2013.7 2991.8 775.5 1130.8 51.0 57.1 45.4 5.8
B6 199.6 269.4 143.5 64.1 508.0 823.1 247.7 291.6 92.6 113.0 56.1 31.7
B7 440.3 556.3 289.4 136.8 1073.1 1586.6 582.6 502.4 115.1 165.7 70.4 47.9
B8 736.2 894.9 604.7 147.0 1336.6 1932.2 1020.4 516.1 311.0 361.8 238.1 64.7
B9 383.5 452.1 344.8 59.6 643.0 706.7 600.3 56.2 193.6 217.5 170.4 23.5
B10 743.5 932.4 564.5 184.1 4151.0 6094.1 1962.4 2076.8 107.9 116.8 92.1 13.7
PM2.5 IN LIVING ROOM (µg/m³)
B1 462.7 540.2 421.1 67.2 1065.1 1380.5 853.4 278.4 157.2 208.0 103.8 52.1
B2 203.2 261.9 138.6 61.7 604.3 1020.8 304.7 372.0 98.0 137.1 56.0 40.6
B3 227.4 310.1 165.5 74.5 512.9 681.1 336.6 172.4 91.5 131.6 71.2 34.7
B4 166.5 199.4 129.8 35.0 419.9 467.4 356.1 57.4 56.4 101.8 32.4 39.3
B5 114.6 119.0 106.5 7.0 282.1 348.6 179.4 90.2 53.8 64.1 47.4 8.9
B6 213.6 282.6 154.1 64.8 499.9 697.9 278.1 210.9 102.5 125.9 62.5 34.8
B7 476.0 589.3 306.7 149.4 1192.3 1638.7 577.9 550.0 132.6 179.2 89.9 44.8
B8 894.6 1092.5 727.9 184.3 1740.2 2256.7 1173.8 543.2 394.8 467.5 333.6 67.7
B9 657.2 1068.7 439.2 356.6 4744.1 12291.2 823.0 6537.7 223.7 282.3 188.1 51.2
B10 417.3 497.5 373.2 69.5 1023.9 1477.5 735.9 397.6 122.7 133.5 113.7 10.0
Chapter Four Results
109
Sampling site B1
Figure 30: Floor plan of sampling site B1
’
Figure 31a: 24-h representative mean values of PM2.5 in kitchen of sampling site B1
0
2000
4000
6000
8000
10000
12000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cooking
involving frying
for gathering of
30 people
Chapter Four Results
110
Figure 31b: 24-h representative mean values of PM2.5 in living room of sampling site B1
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
co
nce
ntr
atio
ns
(µg/m
³)
Hours
Gathering of 30 people
Chapter Four Results
111
Sampling site B2
Figure 32: Floor plan of sampling site B2
Figure 33a: 24-h representative mean values of PM2.5 in kitchen of sampling site B2
0
100
200
300
400
500
600
700
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Cleaning
Cooking
Chapter Four Results
112
Figure 33b: 24-h representative mean values of PM2.5 in living room of sampling site B2
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Ave
rage
PM
2.5
con
cen
trat
ion
s (µ
g/m
³)
Hours
Movement of people
Cooking in
the adjcaent
kitchen
Cleaning
Chapter Four Results
113
Sampling site B3
Figure 34: Floor plan of sampling site B3
Figure 35a: 24-h representative mean values of PM2.5 in kitchen of sampling site B3
0
100
200
300
400
500
600
700
800
900
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Unidentified
Cooking
Chapter Four Results
114
Figure 35b: 24-h representative mean values of PM2.5 in living room of sampling site B3
0
100
200
300
400
500
600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Movement of people
Unidentified
Chapter Four Results
115
Sampling site B4
Figure 36: Floor plan of sampling site B4
Figure 37a: 24-h representative mean values of PM2.5 in kitchen of sampling site B4
0
100
200
300
400
500
600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Unidentified
Cooking
Cleaning
Chapter Four Results
116
Figure 37b: 24-h representative mean values of PM2.5 in living room of sampling site B4
0
50
100
150
200
250
300
350
400
450
500
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking activity in
the partially
connected kitchen
Unidentified
Cleaning
Chapter Four Results
117
Sampling site B5
Figure 38: Floor plan of sampling site B5
Figure 39a: 24-h representative mean values of PM2.5 in kitchen of sampling site B5
0
100
200
300
400
500
600
700
800
900
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
er…
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
118
Figure 39b: 24-h representative mean values of PM2.5 in living room of sampling site B5
0
50
100
150
200
250
300
350
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Movement of people
Chapter Four Results
119
Sampling site B6
Figure 40: Floor plan of sampling site B6
Figure 41a: 24-h representative mean values of PM2.5 in kitchen of sampling site B6
0
50
100
150
200
250
300
350
400
450
500
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
120
Figure 41b: 24-h representative mean values of PM2.5 in living room of sampling site B6
0
50
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150
200
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300
0 1 2 3 4 5 6 7 8 9
10
11
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18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Cooking in nearby
kitchen and
movement of people
Chapter Four Results
121
Sampling site B7
Figure 42: Floor plan of sampling site B7
Figure 43a: 24-h representative mean values of PM2.5 in kitchen of sampling site B7
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
ns
(µg/m
³)
Hours
Unidentified
Cooking
Cleaning
Chapter Four Results
122
Figure 43b: 24-h representative mean values of PM2.5 in living room of sampling site B7
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Ave
rage
PM
2.5
co
nce
ntr
ati
on
(µ
g/m
³)
Hours
Unidentified
Movement
of people
Chapter Four Results
123
Sampling site B8
Figure 44: Floor plan of sampling site B8
Figure 45a: 24-h representative mean values of PM2.5 in kitchen of sampling site B8
0
500
1000
1500
2000
2500
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
CleaningUnidentified
Chapter Four Results
124
Figure 45b: 24-h representative mean values of PM2.5 in living room of sampling site B8
0
500
1000
1500
2000
2500
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking in the
adjacent kitchen
Cigarette
smokingCleaningUnidentified
Chapter Four Results
125
Sampling site B9
Figure 46: Floor plan of sampling site B9
Figure 47a: 24-h representative mean values of PM2.5 in kitchen of sampling site B9
0
100
200
300
400
500
600
700
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Unidentified
Chapter Four Results
126
Figure 47b: 24-h representative mean values of PM2.5 in living room of sampling site B9
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Gas heater for
space heating Unidentified
Chapter Four Results
127
Sampling site B10
Figure 48: Floor plan of sampling site B10
Figure 49a: 24-h representative mean values of PM2.5 in kitchen of sampling site B10
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
co
nce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
128
Figure 49b: 24-h representative mean values of PM2.5 in living room of sampling site B10
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Ave
rage
PM
2.5
co
nce
ntr
ati
on
(µ
g/m
³)
Hours
Movement of people + Cigarette smoking
Cleaning
Cigarette smoking
Chapter Four Results
129
Trends in PM2.5 levels in microenvironments of Category C sampling sites
Sampling sites of category C had a floor area ranging from 278.3 m2 to 506 m2. The
number of occupants varied from 3 to 8 occupants among whom only was a frequent smoker
and carried out smoking indoors. The selected sites were monitored during different seasons
with C1, C9 and C10 monitored during the spring season, C2 during the hot summers, C3
during the rainy season, and C4 monitored during the autumn. The remaining four sites, C5,
C6, C7 and C8 were monitored during the winters. All the selected sites were located within a
radius of 1 Km from main roads with cemented or carpeted adjacent roads in most cases while
the road outside one site was unpaved dust road. The location of the houses was urban with
one house located in industrial area and another in semi-urban and industrial premises. Table
8 provides with an overview of each of the sampling sites.
Floor plans of each site were prepared to assess the spaces present for air exchange as
well as connection between the two microenvironments. It was noted that no direct connection
existed between the kitchens and living rooms in five houses while in three of the houses, doors
of both rooms opened into the same room (partially connected). Kitchen and living room were
directly connected in two houses. The dimensions of the doors and windows along with the
rooms where monitoring was conducted are also given in floor plans (figure 50, 52, 54, 56, 58,
60, 62, 64, 66 and 68).
Since PM2.5 monitoring was carried out for seventy two hours in each house, trends of
PM2.5 were plotted for representative twenty four hours average in both the kitchens and living
rooms. Major activities and the time during which they were performed were identified and
pointed out in a 24-hour period along with PM2.5 levels in each sampling site as shown in figure
Chapter Four Results
130
51a, 51b, 53a, 53b, 55a, 55b, 57a, 57b, 59a, 59b, 61a, 61b, 63a, 63b, 65a, 65b, 67a, 67b, 69a,
and 69b. The 24-hours, hourly maximum and minimum average levels for PM2.5 were
calculated and tabulated in table 9. This data was helpful in comparing the mean and maximum
PM2.5 levels with the background levels (average of hourly minimum) in each house.
The air exchange rate was calculated for both kitchen and living room; once with open
doors and windows to obtain maximum air exchange rate and then with closed doors and
windows to obtain minimum air exchange rates (Annexure-II)
Chapter Four Results
131
Table 8: Profile of Category-C sampling sites
Study
site
Size of
house
(m²)
Occupants Location Type of
road
Distance from
main road
Connection between
kitchen and living
room
Cooking
fuel
No. of
smokers
C 1 506 7 Urban Carpeted 0.5 km Fully connected NG 0
C 2 506 6 Urban Cemented 1 km Not connected NG 0
C 3 455.4 5 Urban Carpeted 0.1 km Not connected NG &
LPG
0
C 4 303.6 5 Urban, Industrial Carpeted 0.1 km Not connected NG 0
C 5 379.5 8 Semi-urban, Industrial Unpaved 1 km Fully Connected NG 14
C 6 379.5 3 Urban Carpeted 0 km Not connected NG 0
C 7 506 7 Urban Carpeted 0.1 km Not connected NG 0
C 8 506 4 Urban Carpeted 0.1 km Partially connected NG 0
C 9 303.6 6 Urban Carpeted 0.1 km Partially connected NG 0
C 10 278.3 6 Urban Carpeted 0.1 km Partially connected NG 0
4 Smoking carried indoors
Chapter Four Results
132
Table 9: Representative 24-h, hourly maximum and hourly minimum averages of PM2.5 recorded in the kitchens and living rooms
of category-C sites
Study
site
PM2.5 IN KITCHEN (µg/m³)
24 HOURS HOURLY MAXIMUM HOURLY MINIMUM
Average Max Min St dev. Average Max Min St dev. Average Max Min St dev.
C1 342.6 441.5 256.7 93.1 1721.7 2365.5 1156.4 608.4 87.1 96.9 71.0 14.1
C2 79.6 107.3 61.7 24.3 193.7 323.2 94.0 117.4 38.5 52.8 29.1 12.6
C3 136.8 165.3 113.8 26.2 319.8 404.0 214.5 96.5 52.3 60.3 43.7 8.3
C4 321.4 355.8 299.4 30.1 1053.3 1290.6 745.7 279.1 75.2 102.8 43.0 30.1
C5 851.8 1089.7 564.4 266.1 1900.8 2760.4 1220.9 785.3 116.2 156.4 77.8 39.3
C6 504.8 536.9 456.5 42.6 916.2 1083 722.7 181.6 218.7 253.7 194.3 31.0
C7 389.0 653.5 166.5 246.2 2474.6 3170.5 1266.2 1050.5 61.3 101.1 37.0 34.8
C8 285.8 337.6 209.0 67.8 554.6 629.2 485.7 71.9 122.2 153.1 78.9 38.6
C9 255.4 333.2 149.8 94.8 453.5 512.1 420.3 50.9 157.0 232.0 34.4 107.0
C10 137.8 217.2 93.4 68.9 1088.4 2495.6 243.3 1226.9 33.1 44.9 25.8 10.3
PM2.5 IN LIVING ROOM (µg/m³)
C1 193.6 228.6 151.6 39.0 502.7 626.5 277.3 195 85.4 93.6 69.1 14.1
C2 68.4 77.3 58.8 9.2 116.1 151.2 86.1 32.8 41.3 50.7 35.0 8.3
C3 137.6 163.4 112.7 25.3 283.4 334.3 195.0 76.9 51.2 66.0 35.2 15.4
C4 388.5 423.7 327.9 52.7 1067.6 1235.0 812.7 224.3 112.9 180.9 53.5 64.1
C5 974.1 1067.3 798.9 151.9 2055.9 2354.9 1697.6 332.6 135.2 183.1 89.4 46.8
C6 729.7 803.1 674.0 66.3 1230.1 1466.1 906.4 290.0 437.7 685.9 278.2 217.8
C7 285.5 443.8 160.3 144.6 797.2 1035.6 477.0 288.1 75.1 123.7 48.9 42.1
C8 386.9 470.2 278.2 98.5 752.7 964.4 604.2 188.2 176.8 233.2 111.5 61.3
C9 449.0 788.5 216.8 300.6 903.2 1352.3 418.7 467.8 258.1 643.6 56.7 333.9
C10 149.0 167.7 122.5 23.6 431.3 461.4 388.3 38.2 49.7 71.7 22.7 24.9
Chapter Four Results
133
Sampling site C1
Figure 50: Floor plan of sampling site C1
Figure 51a: 24-h representative mean values of PM2.5 in kitchen of sampling site C1
0
500
1000
1500
2000
2500
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
134
Figure 51b: 24-h representative mean values of PM2.5 in living room of sampling site C1
0
100
200
300
400
500
600
700
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Movement
of people
Chapter Four Results
135
Sampling site C2
Figure 52: Floor plan of sampling site C2
Figure 53a: 24-h representative mean values of PM2.5 in kitchen of sampling site C2
0
20
40
60
80
100
120
140
160
180
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Chapter Four Results
136
Figure 53b: 24-h representative mean values of PM2.5 in living room of sampling site C2
0
20
40
60
80
100
120
140
160
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Movement of
people
Chapter Four Results
137
Sampling site C3
Figure 54: Floor plan of sampling site C3
Figure 55a: 24-h representative mean values of PM2.5 in kitchen of sampling site C3
0
50
100
150
200
250
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Cooking
Chapter Four Results
138
Figure 55b: 24-h representative mean values of PM2.5 in living room of sampling site C3
0
50
100
150
200
250
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning Movement of
people
Chapter Four Results
139
Sampling site C4
Figure 56: Floor plan of sampling site C4
Figure 57a: 24-h representative mean values of PM2.5 in kitchen of sampling site C4
0
100
200
300
400
500
600
700
800
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Unidentified
Chapter Four Results
140
Figure 57b: 24-h representative mean values of PM2.5 in living room of sampling site C4
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Movement
of people
Unidentified
Chapter Four Results
141
Sampling site C5
Figure 58: Floor plan of sampling site C5
Figure 59a: 24-h representative mean values of PM2.5 in kitchen of sampling site C5
0
200
400
600
800
1000
1200
1400
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Unidentified
Chapter Four Results
142
Figure 59b: 24-h representative mean values of PM2.5 in living room of sampling site C5
0
200
400
600
800
1000
1200
1400
1600
1800
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cigarette
smoking
Unidentified
Gas heater
for space
heating
Chapter Four Results
143
Sampling site C6
Figure 60: Floor plan of sampling site C6
Figure 61a: 24-h representative mean values of PM2.5 in kitchen of sampling site C6
0
100
200
300
400
500
600
700
800
900
1000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Unidentified
Chapter Four Results
144
Figure 61b: 24-h representative mean values of PM2.5 in living room of sampling site C6
0
200
400
600
800
1000
1200
1400
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
co
nce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Movement
of people
Gas heater for
space heating
Unidentified
Chapter Four Results
145
Sampling site C7
Figure 62: Floor plan of sampling site C7
Figure 63a: 24-h representative mean values of PM2.5 in kitchen of sampling site C7
0
200
400
600
800
1000
1200
1400
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
co
nce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
146
Figure 63b: 24-h representative mean values of PM2.5 in living room of sampling site C7
0
100
200
300
400
500
600
700
800
900
1000
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Movement
of people
Chapter Four Results
147
Sampling site C8
Figure 64: Floor plan of sampling site C8
Figure 65a: 24-h representative mean values of PM2.5 in kitchen of sampling site C8
0
100
200
300
400
500
600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Chapter Four Results
148
Figure 65b: 24-h representative mean values of PM2.5 in living room of sampling site C8
0
100
200
300
400
500
600
700
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Activities in the
adjacent kitchen
Chapter Four Results
149
Sampling site C9
Figure 66: Floor plan of sampling site C9
Figure 67a: 24-h representative mean values of PM2.5 in kitchen of sampling site C9
0
50
100
150
200
250
300
350
400
450
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cleaning
Unidentified
Unidentified
Chapter Four Results
150
Figure 67b: 24-h representative mean values of PM2.5 in living room of sampling site C9
0
200
400
600
800
1000
1200
1400
1600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Movement
of people
Cleaning
Unidentified
Chapter Four Results
151
Sampling site C10
Figure 68: Floor plan of sampling site C10
Figure 69a: 24-h representative mean values of PM2.5 in kitchen of sampling site C10
0
100
200
300
400
500
600
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cooking
Cooking and
Cleaning
Chapter Four Results
152
Figure 69b: 24-h representative mean values of PM2.5 in kitchen of sampling site C10
0
50
100
150
200
250
300
350
400
450
500
0 1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Av
erag
e
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Hours
Cleaning
Movement
of people
Chapter Four Results
153
Particulate matter levels in sampling sites
The levels of fine particulate matter are governed by a variety of factors as observed in
this study. PM2.5 concentrations varied in different households and in both micro-environments
under observation (Figure 70).
Figure 70: Mean values of PM2.5 observed in the kitchens and living rooms of the sampling
sites
Since both the kitchen and living room of each house were monitored, Pearson’s Chi-
square correlation test was applied with a significance level of 5 % on the measured PM2.5
levels to observe any association between particulate levels in the kitchens and living rooms
of each site. The null and alternate hypothesis were stated as:
Ho = There is no association between the PM concentrations in kitchen and living room
Ha = There is an association between the PM concentrations in kitchen and living room
0
200
400
600
800
1000
1200
B1
B2
A1
C1
A2
B3
B4
A3
A4
C2
B5
A5
A6
B6
C3
A7
A8
A9
C4
B7
C5
B8
C6
B9
A1
0
C7
C8
B10
C9
C10
PM
2.5
conce
ntr
atio
n (
µg/m
³)
PM2.5 in Kitchens PM2.5 in Living rooms
Chapter Four Results
154
A strong positive correlation among PM2.5 levels in kitchen and living rooms was
observed in 17 houses while a negative correlation was observed in only three houses (table
10).
Table 10: Correlation between PM2.5 levels in kitchens and living rooms of sampling sites
(strong correlations shown in bold) (α = 0.05)
House # Category-A Category-B Category-B
1 0.459 0.858 0.854
2 0.187 0.440 0.874
3 0.978 0.814 0.972
4 0.441 0.998 0.369
5 -0.594 0.137 0.367
6 -0.035 0.503 0.969
7 0.847 0.976 -0.050
8 0.953 0.961 0.991
9 0.309 0.714 0.737
10 0.783 0.640 0.893
Generation of fine particulate matter from various household activities
Each household caries out a number of activities throughout the day which result in the
generation of particulate matter. However each particular activity contributes to varying levels
of PM2.5. The major activities identified in the kitchen included cooking and cleaning while in
the living room cleaning and presence of people were the major contributing activities. Space
heating during the winters and cigarette smoking in some houses were also identified to be
contributing factors. Figure 71a, 71b, 71c, 72a, 72b and 72c represent the average PM levels
generated during the performance of different activities in the kitchens and living rooms of
Chapter Four Results
155
sampling sites respectively. The average PM2.5 along with maximum and minimum levels
generated while performing different activities is summarized in table 11.
Figure 71a: Average PM2.5 levels generated from different activities in kitchen of category-A
sampling sites
Figure 71b: Average PM2.5 levels generated from different activities in kitchen of category-B
sampling sites
-500
0
500
1000
1500
2000
2500
3000
A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
PM
2.5
con
cen
trat
ion
s (µ
g/m
³)
Cooking (Breakfast) Cooking (Lunch + Dinner) Cleaning activities
-1000
0
1000
2000
3000
4000
5000
6000
7000
B1 B2 B3 B4 B5 B6 B7 B8 B9 B10
PM
2.5
con
cen
trat
ion
s (µ
g/m
³)
Cooking (Breakfast) Cooking (Lunch + Dinner) Cleaning activities
Chapter Four Results
156
Figure 71c: Average PM2.5 levels generated from different activities in kitchen of category-C
sampling sites
Figure 72a: Average PM2.5 levels generated from different activities in living room of category-
A sampling sites
-500
0
500
1000
1500
2000
2500
3000
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10
PM
2.5
co
nce
ntr
atio
ns
(µg/m
³)
Cooking (Breakfast) Cooking (Lunch + Dinner) Cleaning activities
0
100
200
300
400
500
600
700
800
A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Movement of people Cleaning Smoking Space heating
Chapter Four Results
157
Figure 72b: Average PM2.5 levels generated from different activities in living room of
category-B sampling sites
Figure 72c: Average PM2.5 levels generated from different activities in living room of category-
C sampling sites
0
500
1000
1500
2000
2500
B1 B2 B3 B4 B5 B6 B7 B8 B9 B10
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Movement of people Cleaning Smoking Space heating
0
200
400
600
800
1000
1200
1400
1600
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10
PM
2.5
conce
ntr
atio
n (
µg/m
³)
Movement of people Cleaning Smoking Space heating
Chapter Four Results
158
Table 11: Overall PM generation observed during different activities in the kitchens and
living rooms
Type of activity Average
(µg/m³)
Maximum
(µg/m³)
Minimum
(µg/m³)
St. Dev
(µg/m³)
Kitchen
Cooking:
Breakfast 884 5779 86 1138
Lunch + Dinner 481 1527 66 390
Cleaning 279 866 61 185
Living room
Movement of people 420 2257 94 340
Cleaning 320 1900 90 348
Smoking 1022 1821 222 513
Space heating 626 1118 354 226
PM2.5 concentrations in connected and not connected kitchens
The connection between kitchens and living rooms was observed to be of significance.
A direct connection between the kitchen and living room existed in only five houses, a partial
connection in six houses while the remaining houses had a variable distance between the both
sites. It was found that in houses where kitchen and living room were connected, the PM levels
of both micro-environments followed almost the same trends while in other two cases (partially
connected and not connected), no direct relation existed. The regression value indicated a
strong relationship between PM levels in both microenvironments where a direct connection
existed (r2 = 0.96) (Figure 73a) while in case of partially connected or not connected rooms,
the value was indicative of a poor relationship among PM values in both microenvironments
(r2 = 0.46 and r2 = 0.43 respectively) (Figure 73b and 73c).
Chapter Four Results
159
Figure 73a: Comparison of 24 hour average PM2.5 in houses with kitchens and living rooms
connected
Figure 73b: Comparison of 24 hour average PM2.5 in houses with kitchens and living rooms
partially connected
y = 1.3918x - 177.54
R² = 0.9658
0
200
400
600
800
1000
1200
0 100 200 300 400 500 600 700 800 900
PM
2.5
in k
itch
ens
PM2.5 in living rooms
y = 0.7384x + 107.39
R² = 0.4584
0
50
100
150
200
250
300
350
400
450
500
0 50 100 150 200 250 300 350 400 450 500
PM
2.5
in k
itch
ens
PM2.5 in living rooms
Chapter Four Results
160
Figure 73c: Comparison of 24 hour average PM2.5 in houses with kitchens and living rooms
not connected
Variations in PM2.5 concentrations during different seasons
Since monitoring of fine particulate matter was conducted in all months of the year, the
obtained results were segregated according to seasons to observe if there was any impact of
seasons upon PM levels or not. As seen in figure 74, highest mean PM2.5 levels were obtained
during the winter season while the summer season exhibited lowest mean concentrations.
y = 0.5526x + 101.11
R² = 0.4354
0
100
200
300
400
500
600
700
800
0 200 400 600 800 1000 1200
PM
2.5
in k
itch
ens
PM2.5 in living rooms
Chapter Four Results
161
Figure 74: Mean levels of PM2.5 obtained during different seasons
In order to test any profound impact of seasons upon particulate matter concentrations
in the sampling sites, the null and alternative hypothesis were formulated as given below:
Ho = Changing seasons have no influence upon fine particulate levels in indoor micro-
environments
Ha = Changing seasons have a strong influence upon fine particulate levels in indoor
micro-environments
The hypothesis were tested using one–way ANOVA. Since the p-values fell in the
critical region, the null hypothesis was rejected and the results indicated a significant influence
0
100
200
300
400
500
600
WINTER SPRING SUMMER MONSOON AUTUMN AVERAGE
PM
2.5
co
nce
ntr
atio
n (
µg/m
³)
PM2.5 in Kitchens PM2.5 in Living rooms
Chapter Four Results
162
of seasons upon PM2.5 levels in both kitchens (p = 0.022) and living rooms (p = 0.005) at a
significance level of 0.05 (table 12a and 12b).
Table 12a: One-way ANOVA for seasonal variation in PM2.5 levels in kitchens
ANOVA
PM.K
Sum of
Squares df Mean Square F Sig.
Between
Groups 537927.140 4 134481.785 3.468 .022
Within Groups 969499.938 25 38779.998
Total 1507427.079 29
Table 12b: One-way ANOVA for seasonal variation in PM2.5 levels in living rooms
ANOVA
PM.LR
Sum of
Squares df Mean Square F Sig.
Between
Groups 707249.308 4 176812.327 4.936 .005
Within Groups 895518.093 25 35820.724
Total 1602767.402 29
Diurnal variations in PM2.5 levels:
Since the major activities in a household are carried out during the day, it was
speculated that there should be a difference in PM concentrations during the day and night
hours. The 24-hour values for particulate matter were segregated according to the length of
day and night. The data for day length was obtained from meteorology department, Lahore.
Chapter Four Results
163
The null and alternative hypothesis were stated as give below and Paired-t test was applied on
PM averages obtained during the day and night hours.
Ho = There is no significant difference in particulate levels during the day and night
hours in the sampling sites
Ha = There is a significant difference in particulate levels during the day and night
hours in the sampling sites
The level of significance was 0.05 and the hypothesis were tested separately for
kitchens and living rooms. The outcome revealed that significant variations existed between
PM levels during the day and night hours in kitchens (t (29) = 0.325, p = 0.747) and the living
rooms (t (29) = -1.496, p = 0.145).
Ventilation rates
Air exchange rate (ACH) was measured under two conditions: once with open doors
and windows, then with closed doors and windows (Annexure-II). Measurements were made
in the absence of people so that CO2 levels may not be affected. The obtained results are given
in figure 75a and 75b below. The flow of air in terms of liter per second per person was also
calculated and is given in table 13.
Chapter Four Results
164
Figure 75a: Maximum and Minimum Air exchange rate in the kitchens of sampling sites
Figure 75b: Maximum and Minimum Air exchange rate in the living rooms of sampling sites
0
2
4
6
8
10
12
14
16
A1
A2
A3
A4
A5
A6
A7
A8
A9
A1
0
B1
B2
B3
B4
B5
B6
B7
B8
B9
B1
0
C1
C2
C3
C4
C5
C6
C7
C8
C9
C1
0
Air
Ch
ange
rate
per
Ho
ur
ACH IN KITCHEN MAX VENTILATION ACH IN KITCHEN MIN VENTILATION
0
1
2
3
4
5
6
7
8
9
10
A1
A2
A3
A4
A5
A6
A7
A8
A9
A1
0
B1
B2
B3
B4
B5
B6
B7
B8
B9
B1
0
C1
C2
C3
C4
C5
C6
C7
C8
C9
C1
0
Air
Ch
nag
e ra
te p
er H
ou
r
ACH IN LIVING ROOM MAX VENTILATION ACH IN LIVING ROOM MIN VENTILATION
Chapter Four Results
165
Table 13: ACH and Air flow rate (liter per second per person) in the kitchens and living
rooms of the sampling sites
Sampling
site
Kitchen Living room
Doors and windows
open
Doors and windows
closed
Doors and windows
open
Doors and windows
closed
ACH L/s/person ACH L/s/person ACH L/s/person ACH L/s/person
A1 7.91 5.60 4.14 0.69 6.78 12.80 3.52 6.65 A2 6.27 7.74 3.19 0.46 3.57 6.74 3.00 5.66
A3 11.07 4.97 11.07 1.58 3.83 6.20 1.97 3.18 A4 4.96 12.65 3.20 0.40 3.51 6.95 1.92 3.80
A5 5.36 4.21 2.79 0.23 7.40 5.82 2.33 1.84 A6 4.82 3.10 3.20 0.53 6.08 14.35 2.49 5.87
A7 11.57 3.25 11.57 1.65 4.75 10.25 2.33 5.02
A8 2.68 1.23 2.67 0.45 5.55 3.64 3.80 2.49 A9 6.26 2.73 2.56 0.20 8.20 7.14 3.75 3.27
A10 11.68 8.04 11.68 2.92 5.34 8.40 2.77 4.36 B1 8.39 4.40 4.99 0.42 6.51 15.35 2.65 6.25
B2 8.32 8.02 4.75 1.19 5.04 12.48 3.44 8.52 B3 5.26 7.44 3.95 0.66 5.66 15.13 2.43 6.50
B4 6.61 14.55 4.24 1.41 5.30 25.00 2.75 12.99
B5 6.60 2.97 3.35 0.48 3.79 7.16 2.32 4.39 B6 7.68 2.64 3.71 0.46 5.42 7.67 3.87 5.48
B7 5.64 7.10 5.64 1.41 5.05 14.28 3.23 9.16 B8 14.97 14.13 14.97 2.50 6.57 6.89 2.04 2.14
B9 4.90 1.19 2.63 0.20 5.50 3.32 2.98 1.81
B10 7.52 2.46 6.69 1.11 2.80 3.53 2.43 3.06 C1 6.01 5.20 3.64 0.52 5.35 14.42 3.78 10.20
C2 5.12 12.08 2.92 0.49 5.48 18.40 4.06 13.63 C3 4.68 3.68 2.48 0.50 6.67 17.62 2.41 6.38
C4 6.74 15.27 2.50 0.50 5.13 15.50 3.20 9.67 C5 10.22 8.68 10.22 1.28 5.11 11.58 2.76 6.25
C6 6.80 11.41 3.91 1.30 8.15 25.63 3.33 10.49
C7 14.51 22.82 2.76 0.39 5.91 11.95 3.40 6.87 C8 11.02 21.66 3.44 0.86 9.12 21.52 3.29 7.75
C9 6.78 3.74 2.95 0.49 4.96 14.06 2.34 6.64 C10 5.40 6.12 3.72 0.62 5.98 9.40 3.46 5.43
Linear regression was applied using SPSS (v 16.0) to observe the impact of ventilation
rates upon the concentrations of fine particulate matter in both micro-environments. The
kitchens exhibited a poor relation between the two parameters while a significant relation
(marked in bold text) was observed in living rooms of Category B and C sites (table 14).
Chapter Four Results
166
Table 14: Regression modeling: ACH versus PM2.5 (α = 0.05)
R2 F P-value
KITCHEN
Category-A 0.277 3.060 0.118
Category-B 0.074 0.637 0.448
Category-C 0.248 2.641 0.143
LIVING ROOM
Category-A 0.109 0.976 0.352
Category-B 0.409 5.528 0.047
Category-C 0.455 6.680 0.032
Levels of bio-aerosols in the sampling sites
The air-borne microflora of the study sites was represented by a total of seven bacterial
species and eleven fungal species. The colony forming units per cubic meter were calculated
for the bacterial and fungal colony counts using the Omelyansky formula. The total bacterial
cfu/m3 ranged from 472 to 9829 in the kitchens and from 275 to 14,469 in the living rooms
(Table 15). Similarly, the total fungal cfu/m3 ranged between 236 and 1887 in the kitchen and
from 314 to 1887 in the living room (Table 16). The average temperature noted during the
monitoring was 27.4oC + 5.6oC in the kitchens and 28oC + 5.6oC in the living rooms while the
average relative humidity levels ranged from 20% to 75% in both the kitchens and living
rooms. The colony forming units of each bacterial and fungal species present in the air of the
monitored sites are given in table 17 and 18. The predominant bacterial species were found to
be Staphylococcus spp. (36.96 % in Kitchens and 35.45 % in Living rooms), Micrococcus spp.
(28.33 % in Kitchens and 29.75 % in Living rooms), and Bacillus spp. (11.75 % in Kitchens
& 14.17 % in Living rooms) along with Serratia spp. and some unidentified Gram negative
and positive rods and Cocci in a few sites (Figure 76a and 76b). Aspergillus fumigatus (25.27
Chapter Four Results
167
% in Kitchens and 22.88 % in Living rooms) and Alternaria alternata (18.86 % in Kitchens
and 30.03 % in Living rooms) were the most abundant fungal species found at all sites along
with some other Aspergillus species, Rhizopus, Fusarium spp. Trichoderma and Mucor (Figure
77a and 77b).
Chapter Four Results
168
Table 15: Temperature, Relative humidity and Total bacterial colony forming units per meter cube (cfu/m3) present in the kitchen and
living room of each sampling site
Sampling site Temperature (°C) Humidity (%) Total number of
colonies in
kitchen
cfu/m3 (Kitchen) Temperature (°C) Humidity (%) Total number of
colonies in living
room
cfu/m3 (Living
room)
A1 18.3 33 49 1927 18 32 37 1455 A2 21 40 13 511 20.5 42 47 1848
A3 27 51 167 6566 26 47 198 7785 A4 36 25 202 7942 35.5 20 164 6448
A5 31.8 59 180 7077 32.1 57 220 8650 A6 30.3 72 88 3460 30.3 72 63 2477
A7 32 65 160 6291 30.4 64 198 7785
A8 33.1 47 168 6605 32 45 190 7470 A9 30.1 48 240 9436 30.1 49 270 10616
A10 32.7 32 151 5937 30.4 33 215 8453 B1 18.1 45 47 1848 18.5 51 11 432
B2 20 55 44 1730 18 55 27 1062 B3 23.4 32 135 5308 23.5 28 10 393
B4 29.9 33 125 4915 29.9 33 115 4522
B5 36.7 36 171 6723 37.9 30 160 6291 B6 32.5 74 164 6448 32.8 74 198 7785
B7 22.8 55 60 2359 22.7 57 74 275 B8 22.6 48 131 5151 22.7 47 170 6684
B9 32.5 20 86 3381 32.8 22 76 2988
B10 20.9 60 20 786 30.3 33 19 747 C1 24.7 46 12 472 26 47 9 354
C2 33.2 31 250 9829 33.2 31 185 7274 C3 30 72 198 7749 30 70 160 6291
C4 29.4 46 210 8257 29.6 45 51 2005 C5 19.7 55 155 6094 19.7 56 38 1494
C6 19.7 56 114 4482 21.5 52 130 5111
C7 26.9 36 83 3263 28 35 229 9004 C8 30.9 37 65 2556 31 38 19 747
C9 25.3 55 240 9436 34.9 29 368 14469 C10 30.9 32 143 5622 32.7 32 181 7116
Chapter Four Results
169
Table 16: Temperature, Relative humidity and Total fungal colony forming units per meter cube (cfu/m3) present in the kitchen and
living room of each sampling site
Sampling site Temperature (°C) Humidity (%) Total number of
colonies in
kitchens
cfu/m3 (kitchen) Temperature (°C) Humidity (%) Total number of
colonies in living
room
cfu/m3 (living
room)
A1 18.3 33 9 354 18 32 12 472 A2 21 40 8 315 20.5 42 10 393 A3 27 51 6 236 26 47 8 315
A4 36 25 19 747 35.5 20 15 590 A5 31.8 59 10 393 32.1 57 11 432
A6 30.3 72 14 550 30.3 72 17 668 A7 32 65 28 1101 30.4 64 25 983
A8 33.1 47 8 315 32 45 28 1101
A9 30.1 48 40 1573 30.1 49 41 1612 A10 32.7 32 48 1887 30.4 33 40 1573
B1 18.1 45 8 315 18.5 51 11 432 B2 20 55 6 236 18 55 9 354
B3 23.4 32 9 354 23.5 28 11 432
B4 29.9 33 13 511 29.9 33 11 432 B5 36.7 36 15 590 37.9 30 32 1258
B6 32.5 74 24 944 32.8 74 39 1533 B7 22.8 55 44 1730 22.7 57 48 1887
B8 22.6 48 20 786 22.7 47 31 1219 B9 32.5 20 28 1101 32.8 22 16 629
B10 20.9 60 10 393 30.3 33 40 1573
C1 24.7 46 7 275 26 47 10 393 C2 33.2 31 28 1100 33.2 31 21 826
C3 30 72 18 708 30 70 27 1062 C4 29.4 46 18 708 29.6 45 30 1180
C5 19.7 55 38 1494 19.7 56 29 1140
C6 19.7 56 34 1337 21.5 52 28 1101 C7 26.9 36 7 275 28 35 9 354
C8 30.9 37 41 1612 31 38 43 1691 C9 25.3 55 11 432 34.9 29 21 826
C10 30.9 32 23 904 32.7 32 24 944
Chapter Four Results
170
Table 17: Colony forming units of each bacterial species identified in the kitchens and living rooms of the sampling sites (*GPC = Gram
Positive Cocci, **GNR = Gram negative Rods, ***GPR = Gram Positive Rods) Site Bacillus spp. Staphylococcus spp. Micrococcus spp. GPC* GNR** GPR*** Serratia spp.
Kitchen Living
room
Kitchen Living
room
Kitchen Living
room
Kitchen Living
room
Kitchen Living
room
Kitchen Living
room
Kitchen Living
room
A1 39 118 904 826 315 511 354 0 315 0 0 0 0 0 A2 432 550 0 983 79 315 0 0 0 0 0 0 0 0
A3 590 275 2241 3106 1769 2320 1691 1022 275 1062 0 0 0 0 A4 944 1180 3657 2084 1376 2516 944 668 944 0 0 0 79 0
A5 1927 2005 1809 3735 2713 2045 0 0 511 865 0 0 118 0
A6 393 315 1966 1533 0 197 0 0 1101 432 0 0 0 0 A7 1140 1769 3067 3342 865 1494 865 0 393 1258 0 0 0 0
A8 629 511 3499 3421 865 2162 668 590 944 786 0 0 0 0 A9 786 2359 3303 2280 2359 4089 550 1455 1297 432 1140 0 0 0
A10 511 1415 2516 2792 1494 2831 865 629 550 472 0 315 0 0 B1 275 0 1455 197 118 236 0 0 0 0 0 0 0 0
B2 0 0 629 354 786 432 236 197 79 79 0 0 0 0
B3 236 432 3106 2045 1337 1455 0 0 629 275 0 0 0 0 B4 1022 1180 826 1101 1730 1415 1337 826 0 0 0 0 0 0
B5 2005 2162 2398 1927 1769 1573 0 629 550 0 0 0 0 0 B6 550 786 3263 2516 1573 2084 354 1455 708 944 0 0 0 0
B7 275 354 1022 1022 472 668 0 315 590 472 0 0 0 0
B8 1022 668 1455 2359 1337 2359 275 747 432 550 629 0 0 0 B9 393 236 1415 629 1022 1337 315 590 236 118 0 0 0 79
B10 0 118 236 275 315 236 157 118 0 0 79 0 0 0 C1 0 39 236 197 236 0 0 118 0 0 0 0 0 0
C2 472 1101 1573 2045 6802 2202 983 747 0 1180 0 0 0 0 C3 354 511 3539 2831 1927 747 786 0 1180 1573 0 629 0 0
C4 1062 157 2398 826 2398 668 432 0 1180 354 708 0 79 0
C5 1022 79 1848 590 1101 668 550 0 826 157 747 0 0 0 C6 275 393 1533 1415 983 2162 708 472 354 668 629 0 0 0
C7 354 747 1101 2909 1219 2674 0 1258 354 550 236 826 0 39 C8 315 157 983 236 550 275 393 79 197 0 0 0 118 0
C9 708 1533 2359 4639 3617 4600 1573 1691 590 1140 432 865 157 0
C10 157 747 1927 2556 2005 1691 629 826 393 786 511 511 0 0
Chapter Four Results
171
Table 18: Colony forming units of each fungal species identified in the kitchens (K) and living rooms (LR) of the sampling sites
Site. Alternaria
alternata
Aspergillus
fumigatus
Aspergillus
nidulans
Aspergillus
flavus
Aspergillus
niger
Aspergillus
terreus
Trichoderma
Rhizopus
Mucor
Fusarium
K LR K LR K LR K LR K LR K LR K LR K LR K LR K LR
A1 79 79 197 315 0 0 39 0 0 0 0 0 0 79 39 0 0 0 0 0 A2 39 157 0 0 79 118 0 0 118 0 0 0 39 0 0 0 0 0 39 118
A3 118 157 0 0 39 39 0 0 0 0 79 0 0 0 0 0 0 0 0 0 A4 79 275 157 79 0 0 0 0 157 39 0 0 0 0 79 0 39 0 236 118
A5 157 0 39 118 0 118 0 0 0 0 39 79 0 0 79 0 0 118 79 0 A6 79 236 275 79 79 0 0 0 39 39 0 39 0 0 0 0 79 0 0 236
A7 197 0 157 275 39 0 315 0 275 0 0 157 0 0 0 0 0 0 118 118 A8 0 472 79 0 0 79 0 0 0 79 39 0 0 0 39 354 0 0 0 0
A9 511 393 315 275 157 0 0 0 0 354 275 0 0 197 0 0 275 315 0 79
A10 432 511 550 472 157 0 0 0 79 0 118 236 0 0 275 0 0 0 157 315 B1 157 118 0 0 0 0 39 39 39 0 39 79 0 0 0 0 0 0 39 39
B2 79 79 118 157 39 39 0 0 0 79 0 0 0 0 0 0 0 0 0 0 B3 118 79 79 118 0 0 0 39 0 0 39 39 0 0 0 0 79 118 39 0
B4 79 79 197 236 0 0 39 0 0 0 0 0 79 0 0 118 118 0 0 0
B5 197 393 39 275 197 0 0 0 79 275 0 0 0 0 0 79 0 0 79 197 B6 157 668 39 0 0 354 275 275 118 0 0 0 0 0 118 0 79 197 39 0
B7 79 708 0 432 0 0 236 0 0 0 0 118 0 197 79 39 0 0 0 236 B8 157 432 118 0 0 236 79 0 0 0 0 315 275 0 79 0 39 236 39 0
B9 157 118 315 0 275 0 0 0 354 0 0 354 0 0 0 0 0 0 0 118 B10 0 668 236 354 0 118 0 0 0 0 0 275 0 0 79 0 79 157 0 0
C1 0 0 118 79 0 0 39 79 0 0 0 118 0 0 0 39 39 0 0 0
C2 157 432 236 79 0 0 197 118 0 0 157 0 118 197 0 0 157 0 0 0 C3 0 354 118 275 0 0 0 0 0 118 157 0 197 0 0 236 197 0 0 0
C4 39 472 118 197 0 0 236 354 315 0 0 157 0 0 0 0 0 0 0 0 C5 275 354 629 550 79 0 0 0 0 118 39 0 157 0 0 0 0 0 275 0
C6 157 0 472 590 0 0 157 275 0 0 118 0 0 0 79 0 275 0 0 157
C7 0 0 118 197 0 0 118 0 0 118 0 0 0 39 0 0 39 0 0 0 C8 315 79 432 747 354 0 0 157 157 0 157 0 39 393 0 0 0 0 79 118
C9 79 550 236 0 0 0 0 275 39 0 39 0 0 0 39 0 0 0 0 0 C10 275 236 197 275 0 0 0 0 39 79 0 0 0 0 0 0 236 0 0 354
Chapter Four Results
172
Figure 76a: Proportion of bacterial species present in the kitchens of the sampling sites
Figure 76b: Proportion of bacterial species present in the living rooms of the sampling sites
Bacillus spp
Staphylococcus spp
Micrococcus spp
GPC*
GNR**
GPR***
Serratia spp
Bacillus spp
Staphylococcus spp
Micrococcus spp
GPC*
GNR**
GPR***
Serratia spp
Chapter Four Results
173
Figure 77a: Proportion of fungal species present in the kitchens of the sampling sites
Figure 77b: Proportion of fungal species present in the living rooms of the sampling sites
Alternaria alternata
Aspergillus fumigatus
Aspergillus nidulans
Aspergillus flavus
Aspergillus niger
Aspergillus terreus
Trichoderma
Rhizopus
Mucor
Fusarium sp
Unidentified
Alternaria alternata
Aspergillus fumigatus
Aspergillus nidulans
Aspergillus flavus
Aspergillus niger
Aspergillus terreus
Trichoderma
Rhizopus
Mucor
Fusarium sp
Unidentified
Chapter Four Results
174
Statistical analysis
The relationship between air-borne microflora and various parameters noted during the
monitoring of bio-aerosols was determined using SPSS (v.16.0.0). The selected independent
parameters were temperature, relative humidity, and air change rate per hour and the dependent
variables were bacterial cfu/m3, fungal cfu/m3 and PM2.5 levels. Linear regression was applied
on single and multiple variables. Temperature was found to have a direct relationship with
bacteria and particulate matter but not fungi. Ventilation also had a significant relation with
particulate matter (Table 19 and 20).
Table 19: Regression modeling of different parameters in kitchen (α = 0.05). Significant results
are marked in bold text.
19a: Bacteria (cfu/m3)
r2 F p-value
Temperature 0.341 14.465 0.001
Relative Humidity 0.002 0.051 0.823
Air change per hour 0.035 1.018 0.322
Temperature & RH 0.361 7.628 0.002
Temp., RH & ACH 0.396 5.676 0.004
19b: Fungi (cfu/m3)
r2 F p-value
Temperature 0.043 1.263 0.271
Relative Humidity 0.002 0.048 0.828
Air change per hour 0.038 1.105 0.302
Temperature & RH 0.043 0.609 0.551
Temp., RH & ACH 0.088 0.841 0.484
Chapter Four Results
175
19c: PM2.5 (µg/m³)
r2 F p-value
Temperature 0.146 4.773 0.037
Relative Humidity 0.000 0.013 0.909
Air change per hour 0.123 3.943 0.057
Temperature & RH 0.153 2.443 0.106
Temp., RH & ACH 0.256 2.977 0.050
Table 20: Regression modeling of different parameters in living room (α = 0.05). Significant
results are marked in bold text.
20a: Bacteria (cfu/m3)
r2 F p-value
Temperature 0.324 13.407 0.001
Relative Humidity 0.003 0.073 0.789
Air change per hour 0.095 2.941 0.097
Temperature & RH 0.332 6.711 0.004
Temp., RH & ACH 0.338 4.434 0.012
20b: Fungi (cfu/m3)
r2 F p-value
Temperature 0.064 1.921 0.177
Relative Humidity 0.032 0.914 0.347
Air change per hour 0.000 0.006 0.940
Temperature & RH 0.125 1.933 0.164
Temp., RH & ACH 0.166 1.729 0.186
20c: PM2.5 (µg/m³)
r2 F p-value
Temperature 0.205 7.242 0.012
Relative Humidity 0.007 0.207 0.653
Air change per hour 0.235 8.600 0.007
Temperature & RH 0.206 3.506 0.044
Temp., RH & ACH 0.340 4.472 0.012
Chapter Four Results
176
Seasonal variation in bioaerosol levels
Since the sampling was carried out during different seasons, one way ANOVA was
applied to determine the impact of season upon bacterial and fungal levels in indoor
environments. The null and alternate hypothesis were stated as:
Ho = Changing seasons have no significant impact upon bioaerosol levels in the
kitchens and living rooms of the sampling sites
Ha = Changing seasons have a significant impact upon bioaerosol levels in the kitchens
and living rooms of the sampling sites
A significant impact of season was observed upon bacterial and fungal levels in the
kitchens as the p-values did not fall in the critical region (p = 0.035 and p = 0.045 respectively)
while in the living rooms, the effect upon bacterial and fungal levels was not pronounced (p =
0.53 and p = 0.60 respectively) (Table 21).
Chapter Four Results
177
Table 21: One-way ANOVA for seasonal variation in bioaerosol levels in the kitchens and
living rooms
ANOVA
Sum of Squares df Mean Square F Sig.
BACTERIA_K Between Groups 7.167E7 4 1.792E7 3.067 .035
Within Groups 1.460E8 25 5841891.821
Total 2.177E8 29
BACTERIA_LR Between Groups 4.613E7 4 1.153E7 .811 .530
Within Groups 3.556E8 25 1.422E7
Total 4.017E8 29
FUNGI_K Between Groups 2215138.228 4 553784.557 2.708 .053
Within Groups 5111668.243 25 204466.730
Total 7326806.471 29
FUNGI_LR Between Groups 1951916.889 4 487979.222 2.606 .060
Within Groups 4681953.138 25 187278.126
Total 6633870.027 29
Association between PM2.5 levels and bio-aerosols
Since bioaerosol sampling was conducted for twenty minutes only, PM2.5 levels were
separated from the 24-hour data for those specific twenty minutes to observe any significance
between the both parameters. The respective highest and lowest mean levels of PM2.5 observed
during twenty minutes of bioaerosol sampling were noted to be 700.4 + 71.8 µg/m³ and 40.8
+ 15.3 µg/m³ in the kitchen and 809.5 + 54.5 µg/m³ and 39.6 + 5.6 µg/m³ in the living room.
Although there are a few limitations such as use of passive sampling for bio-aerosols and real-
time monitoring for particulate matter, this comparison was an attempt to observe if any
association existed or not. The null and alternative hypothesis were devised as:
Ho = There is no significant association between bio-aerosol levels and fine particulate
matter
Chapter Four Results
178
Ha = There is a significant association between bio-aerosol levels and fine particulate
matter
The results revealed no substantial association between the sampling sites and any of
the measured variables. Moreover, no significant correlation was observed to exist between
PM levels and bioaerosols (Table 22).
Table 22: One-way ANOVA for association between bioaerosol levels and PM2.5 in the
kitchens and living rooms
ANOVA
Sum of Squares df Mean Square F Sig.
Bac_kit Between Groups 2.206E7 2 1.103E7 1.522 .236
Within Groups 1.957E8 27 7246599.904
Total 2.177E8 29
Bac_LR Between Groups 5.365E7 2 2.683E7 2.081 .144
Within Groups 3.481E8 27 1.289E7
Total 4.017E8 29
Fungi_kit Between Groups 190417.123 2 95208.561 .360 .701
Within Groups 7136389.348 27 264310.717
Total 7326806.471 29
Fungi_LR Between Groups 151598.785 2 75799.392 .316 .732
Within Groups 6482271.242 27 240084.120
Total 6633870.027 29
PM2.5_kit Between Groups 72534.707 2 36267.354 1.134 .336
Within Groups 863161.973 27 31968.962
Total 935696.680 29
PM2.5_LR Between Groups 211433.585 2 105716.792 2.560 .096
Within Groups 1115024.080 27 41297.188
Total 1326457.665 29
Chapter Five Discussion
179
CHAPTER FIVE
DISCUSSION
Particulate matter and bio-aerosols are two of the most important air-borne pollutants
that have a detrimental impact on human health (Kowalski, 2006; Tiwary and Colls, 2010).
The results obtained in this study revealed that both the PM and bio-aerosol levels were highly
exceeding the recommended limits in both the kitchens and living rooms of the houses under
observation.
The observations of this research explored the air quality of kitchens and living rooms
of the selected sites from various locations of the city. As obvious in figure 7, 8 and 9, most of
the occupants in the selected households belonged to the age group of 21-30 years (29 % males
and 31 % females) with majority of them being students or job holders. Therefore, a large
number of occupants spent variable time at home. It was the children below 5, females
(particularly housewives) and the elderly that spent maximum time in house. According to the
obtained data, only 20% of males spent 17-24 hours in the house whereas 62% of females were
observed to be spending their time i.e. 17-24 hours indoors. However, despite of such a
variation in the time spent by males and females at home this did not mean that the male
occupants were less exposed to pollutants in the indoor environments as compared to females.
Their exposure level may in fact be higher than females as they travel daily to work, are
exposed to a multitude of pollutants at work and on road as well. However, this research
focusses on the pollutant levels in houses and here females were observed to be more exposed
to indoor PM2.5 while performing different activities like cooking and cleaning within the
house.
Chapter Five Discussion
180
Several internal and external factors affect indoor air quality such as the location and
design of the building, ventilation practices in use, seasonal variation, meteorological factors,
number of people occupying the room, use of room (such as office, waiting room, bedroom,
living room, and kitchen) (Goyal and Khare, 2010; Massey et al., 2012). For instance, an
important factor that influenced PM2.5 levels was the connection between the two monitored
rooms. In five houses, where the door of kitchen opened into the living room, the trends in
particulate levels over the 24-hours period were almost the same (sampling site B2, B7, B8,
C1, and C5). In these houses, activities in the kitchen were found to significantly affect the
particulate levels in the living rooms as well. Similarly, in houses where the doors of kitchen
and living room opened into the same room (sampling sites A3, A7, A10, C8, C9, and C10)
the activities in the kitchens did influence the PM levels in the living rooms but not so strongly
while being absent altogether in houses where both rooms were far apart.
Domestic activities have been observed to significantly affect the indoor air quality by
many researchers (Jhang and Smith, 2003; Ferro et al., 2004; Meng et al., 2005). Chao and
Cheng (2002) identified five different sources of PM2.5 in eight different houses which included
cooking, burning incense, smoking, indoor human activities, and ambient sources. Likewise,
this research also identified major indoor activities that could have a significant contribution
towards elevating the pollutant levels. The kitchens have been documented in many studies to
harbor an elevated level of particulate matter owing to the increased activity levels within its
premises. Cooking is also a major contributor in this regard as the cooking fuel used and the
method employed for cooking causes variations in pollutant levels (Naeher et al., 2000; Lee et
al., 2002; Colbeck et al., 2008; Isaxon et al., 2015). However in the current study, cooking fuel
did not have a strong influence as it was natural gas in all houses which is a comparatively
Chapter Five Discussion
181
much cleaner and safer fuel than the biomass fuel (Siddiqui et al., 2009; Shimada and
Matsuoka, 2011; Saeed et al., 2015). Nevertheless, cooking practices were a potential factor
that were observed to strongly affect particulate levels. In Pakistan, meals are taken three times
a day with most of the cooking done by female members of the house. Frying of most of the
food items is an essential part of cooking. The general breakfast includes making of ‘Parathas’
which is a traditional fried flat-bread most commonly eaten in breakfast in Pakistan
accompanied by fried eggs or omelets. Similarly the lunch and/or dinner table is incomplete
without food items cooked by frying. Frying has been recognized to lift PM2.5 levels 30 times
more than the background values while grilling was recorded to increase the levels by 90 times
(He et al., 2004). Comparable observations have been described by Huboyo et al. (2011) and
Nasir and Colbeck (2013) and in the current results too, it was observed that in kitchens where
more frying was carried out, PM levels were also higher. The 24-hours representative PM2.5
values were useful in highlighting the effect of cooking upon PM levels. Higher peaks were
observed in majority of households where ‘Parathas’ were made in the breakfast. In fact PM2.5
levels were higher during breakfast preparation in these houses as compared to levels
throughout the day. The best examples in this regard can be given for sampling site A3, A6,
A10, B1, B10, C1, C7, and C8 where pronounced peaks were observed during cooking time.
In A3, the occupants left the house early in the morning as all the children were students
and both parents were schools teachers. The breakfast comprised of bread and tea while no one
was present during the lunch hours. Dinner was the major meal of the family and PM levels as
high as 2355 µg/m³ were observed during that hour as compared to 298 µg/m³ during the
breakfast time.
Chapter Five Discussion
182
Sampling site A6 was monitored during the holy month of Ramadan5 so there were
only two meals in the day. Only two peaks were prominent throughout the day i.e. during the
“sehri” when “Parathas” were made and during “iftaar” when less frying was done with
respective PM levels to be as high as 3666 µg/m³ and 757 µg/m³.
In house A10, breakfast was the major meal and again ‘Parathas’ were an essential
component. Mean PM2.5 levels were observed to be 2639 µg/m³ during that time. In sampling
site B1 as well, ‘Parathas’ were made in breakfast and in large numbers due to a gathering of
around 30 people in the house. The mean PM2.5 levels were recorded to be 9597 µg/m³ during
breakfast (noted to be the highest levels generated by cooking so far in this study) while
masking the PM levels generated from other sources.
In sampling site B10, three prominent peaks were observed at the time of cooking of
meals. Again the highest peak (4396 µg/m³) was observed during the breakfast. Same was the
case in C1, where particulate levels rose to 2365 µg/m³ during the breakfast. In sampling site
C7, again three peaks were pronounced during the 24-hours PM averages with PM2.5 levels as
high as 1266 µg/m³ during the breakfast time. Similarly in house C8, PM2.5 levels were higher
while breakfast preparation (486 µg/m³) than during the rest of the day.
These examples provide an evidence as how cooking, particularly frying can result in
high amounts of PM2.5 generation in the kitchens. As seen in table 11 as well, highest average
PM2.5 levels were noted during the time of breakfast preparation (884 µg/m³) while during
lunch and dinner preparations these levels were reduced to half (481 µg/m³). Apart from
cooking the second major activity was identified to be cleaning which included floor sweeping,
dusting of surfaces and material movement. The mean PM2.5 levels generated during cleaning
5 The ninth month of Islamic calendar during which the Muslims fast during the day. The first meal or “sehri” is
taken before the dawn and the second meal of “iftaar” that concludes the fast is taken after sunset.
Chapter Five Discussion
183
activities were 279 µg/m³. PM levels during cleaning were, however, still less than levels noted
during cooking.
Comparatively, the living rooms are an entirely different environment than the kitchens
with its own particular set of activities and sources. The activities carried out in the living
rooms included smoking, floor sweeping, dusting of surfaces, and also movement of people
which had a significant impact upon the PM levels in the rooms. Although smoking was
observed to be carried out within the houses in only four cases, the mean PM2.5 levels generated
were 1022 µg/m³ with levels reaching as high as 1821µg/m³. Smoking is known to increase
PM levels significantly (Monn et al., 1997; He et al., 2004; Colbeck et al., 2008; Nafees et al.,
2011; Nasir and Colbeck, 2013). Tobacco smoke has been identified as a source of heavy
metals by Ruggieri et al. (2014) while a significant association between asthma in children and
exposure to second hand smoke was observed by Bilocca et al. (2014).
Significant contribution from use of gas heaters was also noted, as during space heating,
maximum PM2.5 levels were recorded to be 1118µg/m³. Peaks were noted during the mornings
as the occupants were in a haste while getting ready for work or school etc. and during evenings
as they returned home. Highest levels observed during this time were 2257 µg/m³. Although
movement of people may not generate particulate matter in itself, occupant’s movement in a
room has been associated with the resuspension of already deposited particulate matter this
includes PM deposited on surfaces (Ferro et al., 2004). Personal activities have been associated
with increased PM levels indoors (Van Ryswyk et al., 2014). Rapid movement while getting
ready for work or school should, therefore, be an important contributor towards elevating the
levels of fine particulate matter in indoor micro-environments as perceived in the results of
Chapter Five Discussion
184
this study as well. The obtained results were similar to those observed in many other studies
such as Chao et al. (1998), Jones et al. (2000), Colbeck et al. (2008), and Bhangar et al. (2011).
A substantial difference in the diurnal patterns of particulate matter was witnessed
during the study. Although there is not much data on diurnal variations of particulate matter in
the indoor micro-environments, a significant difference in day and night averages has been
recently reported in the ambient air of four major cities of Pakistan by Rashed et al. (2015).
Another observation pertaining to levels of PM2.5 levels indicated that in some houses,
particulate levels peaked at or around midnight even in the absence of any obvious source.
Such observations were documented in both the kitchens and living rooms of sampling sites
A2, A7, A9, B3, B, B7, B8, B9, C4, C5, C6, and C9 where a sharp peak was seen at or after
mid-night. Most often, such peaks are observed during the winters when particles are not easily
dispersed due to low kinetic energy. However, interestingly these sites were sampled during
different times of the year and so season could not be the causing reason of such unexpected
behaviour. It is possible that some metrological phenomenon might be the cause of these
elevated levels and to obtain a clearer understanding, this process needs to be reproduced with
simultaneous real time monitoring of indoor/outdoor PM, temperature, relative humidity and
other meteorological parameters. Since these high levels could not be related to ant particular
source, they were labelled as unidentified source in the 24 hour representative graphs of PM2.5
given in the results section.
The 24-h average levels of particulate matter were manifolds higher than the
established standards. Apart from that, the hourly maximum and minimum PM2.5 levels were
also indicative of poor air quality. Even the background levels (hourly minimum) were
observed to be higher than the safety limits. The mean background levels for particulate matter
Chapter Five Discussion
185
in the kitchen were 103+62 µg/m³ and 124+97 µg/m³ in the living room. These levels were 4
to 5 times higher than the WHO recommended limits. In the absence of any activity, the highest
PM background levels were noted to be 311 µg/m³ in the kitchens and 438 µg/m³ in the living
room while the lowest background concentrations were 33 µg/m³ and 41 µg/m³ in the kitchen
and living room respectively. These results signify an immediate need to implement an air
quality management plan, as prolonged exposure to such high levels can produce substantial
adverse health impacts.
Apart from indoor sources, pollutant levels are greatly affected by outdoor levels.
There are numerous studies that have reported ambient sources to be equally responsible for
defining indoor air quality such as those of Chunram et al. (2007) and Ali et al. (2015a). Since
ambient sampling was not conducted in the current research, it is difficult to say for sure if
outdoor sources played any significant part in defining the obtained results for PM2.5 levels.
Although there are many unexplained peaks observed in the 24-hours representative graphs
of PM2.5 in both the rooms, their source remains unidentified and could have an association
with activities in the surroundings. The trend followed by PM2.5 levels in the ambient air of
Lahore is increasing with annual mean levels to be 123 µg/m³ in 2008, 129 µg/m³ in 2009 and
136 µg/m³ in 2010 as monitored by Environment Protection Department, Government of the
Punjab6 (Annexure-III). Many studies on ambient air quality of Lahore have recognized high
levels of PM2.5 being generated from various sources with vehicular emissions being the prime
factor (Lodhi et al., 2009; Ali et al., 2015c; Nasir et al., 2015c; Rasheed et al., 2015). The
severity of health outcomes from vehicular emissions has led to the recent recommendations
by UK government that PM2.5 is used to judge the influence of combustion sources including
6 Data obtained from the office of Deputy Director Labs, Environmental Protection Department-Government of
the Punjab.
Chapter Five Discussion
186
road traffic instead of PM10 (Moorcroft and Barrowcliffe et al., 2105). With the ambient levels
exceeding the NEQS manifold, this fact cannot be ignored that indoor air quality may also be
affected by outdoor levels of pollutants.
A persistent source of fresh air in the indoor environments is a central factor to sustain
a healthy environment. Natural ventilation is economical than mechanical ventilation but it is
also uncontrolled as the airflow is unpredictable under changing climate. Moreover the
opening and closing of windows and any other such openings such as cracks and fixtures in
buildings also influence the infiltration of outdoor air (Allard, 2002). Ventilation practices
contribute significantly in defining the air quality of any indoor environment as the infiltration
and exfiltration rates are dependent upon it. Climate also plays an influential role in the form
of a limiting factor when designing and constructing buildings which are naturally ventilated.
Since Lahore is located in the tropical zone and characterized by a semi-arid hot climate,
winters are relatively short with long, hot summers. Therefore it is natural for people to keep
the windows open for most part of the day. Natural ventilation is more suitable in areas with
mild climate (Kowalski, 2006) and all the selected houses for this study were naturally
ventilated as is the common practice in Lahore.
Naturally ventilated buildings tend to be leaky and allow adequate air circulation in
and out of the building, thereby providing the residents with an incessant supply of fresh air.
Still dead spots may be present within the buildings with little or no air exchange at all. This
constant circulation of air in and out of the building envelope has often proved to have a
detrimental effect upon indoor air quality as the ambient air entering the building may be laden
with pollutants. A recent research by Nimra et al. (2015) on indoor air quality of operation
theatres signified the importance of an effective ventilation system as particulate
Chapter Five Discussion
187
concentration was observed to be minimum in the presence of a laminar flow system but where
natural ventilation was applied, the air quality was questionable. However along with causing
infiltration of pollutants in to the building matrix, constant air change also ensures dilution of
the indoor air and helps in reducing the accumulation of pollutants in indoor micro-
environments (Helmis et al., 2007; Abdel-Salam, 2015). A study by Nasir and Colbeck (2013)
also highlighted the importance of ventilation in reducing pollutant loads in residential
apartments of UK as they noted PM levels to drop to half during the summers in smoking
apartments.
The rate of air change as observed in this research was noted to be lower than the
recommended values. Minimum ACH in any indoor environment should be 4 ACH which
means that air is replaced after every fifteen minutes or four times in an hour. Similarly the
kitchens should also be well ventilated with an air exchange rate of no less than 15 ACH.
However, the air change rate may fluctuate with the building requirements, floor area and the
dwellers living in the building. According to ASHRAE standard 62.2-2013, the minimum level
of ventilation in naturally ventilated buildings should be 3.5 L/s/person or 7.5 cubic feet per
minute/person (CFM/person) to guarantee a healthy setting for the inhabitants. According to
WHO guidelines for indoor air quality (2009), ventilation rates below 10 l/s per person are
associated with significantly advanced occurrence of one or more health consequences or with
poorer perceived air quality in office settings (Seppänen, et al., 1999) whereas ventilation rates
more than 10 l/s per person, nearly 20–25 l/s per person, are related with a substantial reduction
in the frequency of indications of sick-building syndrome or with enhanced perceived air
quality in workplace environments (Seppänen, et al., 1999; Sundell and Levin, 2007).
Chapter Five Discussion
188
As the results indicate, the ventilation rate was not adequate in both the kitchens and
living rooms in most cases. Only the semi-open kitchens had an ACH of 10-15 while in most
cases the ACH was below 10. In the living rooms, the ACH ranges between 2 and 9 air changes
per hour. One important aspect to be remembered is that these rates are merely representative
values and may not reflect the original air exchange rates which are always a difficult aspect
to be measured due to leaks or small opening from where air can enter the room. The rates
were once measured with the doors and windows open and again with closing all such spaces
while in actual practice it is possible that only one window or only the door was kept open for
most part of the day and not all spaces be utilized for ventilation. Determination of ventilation
according to the number of occupants was also calculated to observe how much air was
available per person. Here it was seen that although in case of maximum ACH i.e. when all
doors and windows were open, there was adequate air for the occupants at most sites, but there
was a tremendous decline in air circulation if all the windows and doors were closed as it was
observed to be a common practice during the winters (Table 13). Besides the maximum ACH
or l/s/person values do not reflect the actual ventilation rates as explained above.
There are a number of factors that may be held responsible for such low levels of
ventilation including poor building design thereby allowing inefficient air exchange with the
outdoor air. Moreover there are some other limitations as well such as determining the actual
ventilation rate in naturally ventilated buildings can prove to be difficult. Meteorological
factors such as local wind speed and ambient temperature are the governing factors while the
number of windows is also an equally contributing factor (Chao and Wong, 2002; Kowalski,
2006; Helmis et al., 2007).
Chapter Five Discussion
189
Bioaerosols are also an important component of the indoor air. There are many
influencing factors that determine the indoor bio-aerosol levels including temperature, relative
humidity and human beings as well. In fact human beings are considered the biggest source of
indoor air-borne micro-organisms (Mentese, 2009; Mentese et al., 2012; Oh et al., 2015).
Although the method used in this study was passive sampling (Koch sedimentation method),
it is still a useful tool for documenting the species composition of any environment
(Stryjakowska-Sekulska et al., 2007). The bacterial and fungal species identified in the
sampling sites were recognized to be a common constituent of the indoor air and opportunistic
pathogens as well. The prevalence of the identified speices varied from room to room and
house to house.
Abundant bacterial species recorded from the sampling sites included Staphylococcus
spp., Micrococcus spp. and Bacillus spp. The fungal micro-flora, on the other hand, comprised
of Aspergillus fumigatus and Alternaria alternata being the most prevalent with Aspergillus
species, Rhizopus, Fusarium spp. Trichoderma and Mucor were also present in varying
concentrations. Investigations by other researchers have also reported a somewhat similar
micro-biota in the indoor environments. An investigation of Polish homes revealed
Micrococcus spp. to be present at all sites with Staphylococcus epidermidis being second in
number. The fungal composition included species such as Absidia glauca, Alternaria
alternata, Cladosporium cladosporioides and Penicillium aurantiogriseum in most of the
sampled sites (Pastuszka et al., 2000). Likewise Aeromonas, Bacillus, Kocuria, Micrococcus,
Nocardia, Pseudomonas, and Staphylococcus were common bacterial species reported from
indoor residential environments while Aspergillus, Penicillium and yeasts predominated the
fungal fauna (Gorny and Dutkiewicz, 2002). Karwowska (2003), Gorny (2004) and Haas et al.
Chapter Five Discussion
190
(2007) observed Aspergillus and Penicillium to be the most dominant genera in the indoor
environment while Lee and Jo (2006) documented the presence of Alternaria and
Cladosporium in addition to these genera. Reboux et al. (2009) also reported higher levels of
Aspergillus, Penicillium and Cladosporium in unhealthy houses with visible mold. Recently
the presence of bacterial species Brevibacillus brevis, Arthrobacter and Bacillus cereus and
fungal species of Neosartorya fischeri, Aspergillus clavatus and Trichoderma in indoor air
were reported by Joshi and Srivastava (2013).
Among the common fungal speices, Aspergillus and Penicillium have been reported to
be life threatening pathogens, particularly for immuno-compromised people (Vonberg and
Gastmeier, 2006; Basilico et al., 2007). Similarly, Aspergillus, Alternaria, Fusarium and
Cladosporium are responsible for asthma, sinusitis, rhinitis and many other hypersensitivity
reactions (Hardin et al., 2003; Kalogerakis et al., 2005). Salo et al. (2006) observed an increase
in asthma symptoms with increase in exposure to Alternaria alternata in US homes. Nasir and
Colbeck (2010) also observed wide variation in the levels and size of air-borne microbes in
fifteen residencies reflecting the diversity in behaviour and the exposure to high risk indoors.
A description of the observed microbial species as well as their potential sources and
susceptible sites of entry have been summarized in Table 23.
Though species of Cladosporium and Penicillium were absent at the selected sampling
sites in the present research, other species were present in variable numbers. On questioning
the occupants regarding their health status, it was found out that one or two occupants in sixteen
households suffered from allergic reactions to dust or during wheat harvesting season. One out
of the nineteen reported occupants was an asthma patient with no family history of asthma.
Although previous studies have concluded lack of association between bioaerosols and non-
Chapter Five Discussion
191
biological particulate matter in residential settings (Pastuszka et al., 2000; Hargreaves et al.,
2003), there is a possibility that the presence of such elevated levels of bioaerosols and
particulate matter and their synergistic effect could have contributed to these adverse health
outcomes as reported in this research.
Table 23: Sources and health hazards posed by the observed bacterial and fungal species
(Source: Kowalski, 2006).
BACTERIA Description Natural Sources Diseases caused Point of
infection
Suggested
indoor limit
Staphylococcus
spp.
Gram positive
bacteria, non-
communicable,
opportunistic
pathogen
Humans, sewage,
nosocomial.
staphylococcal
pneumonia,
opportunistic
infections
Upper
Respiratory
Tract
NA
Micrococcus
spp.
Gram positive
bacteria, non-
communicable,
opportunistic
pathogen
Skin of humans
and other animals
and in soil, marine
and fresh water,
plants, dust, and
air
Pneumonia,
septic arthritis,
endocarditis,
bacteremia and
meningitis
Upper
Respiratory
Tract, skin
NA
Serratia spp. Gram negative
bacteria,
opportunistic
pathogen
Environmental,
indoor growth in
potable water,
nosocomial.
Opportunistic
infections,
bacteremia,
endocarditis,
pneumonia.
Upper
Respiratory
Tract, wounds,
eyes, urinary
tract
NA
FUNGI
Aspergillus spp. Non-
communicable,
causes
Aspergillosis, also
associated with
sick building
syndrome
Environmental,
nosocomial,
indoor growth on
insulation & coils.
Aspergillosis,
alveolitis,
asthma, allergic
fungal sinusitis,
ODTS, toxic
reactions,
pneumonia
possible
Upper
respiratory tract
150-500 cfu/m3
Alternaria
alternata
Non-pathogenic,
non-
communicable,
common indoor
contaminant, can
cause
opportunistic
Environmental,
indoor growth on
paint, dust, filters,
& cooling coils.
Allergic
alveolitis,
rhinitis, sinusitis,
asthma, toxic
reactions
Upper
respiratory tract
150-500 cfu/m3
Chapter Five Discussion
192
allergic reactions
and contribute to
sick building
syndrome
Mucor Non-
communicable,
opportunistic
pathogen
Environmental,
sewage, dead plant
material, horse
dung, fruits.
Mucormycosis,
rhinitis,
pneumonia
Upper
respiratory tract
150-500 cfu/m3
Trichoderma Non-
communicable,
allergenic
Environmental,
soil, wood,
decaying
vegetation.
Allergic
alveolitis, toxic
reactions,
MVOCs
Upper
respiratory tract
150-500 cfu/m3
Rhizopus Non-
communicable,
opportunistic
pathogen
Environmental,
decaying fruit and
vegetables,
compost.
Zygomycosis,
allergic reactions,
pneumonia,
mucormycosis.
Upper
Respiratory
Tract, sinus,
skin eyes
150-500 cfu/m3
Fusarium spp. Non-
communicable,
allergenic
Environmental,
indoor growth on
floor dust filters, &
in humidifiers.
Allergic
alveolitis, allergic
fungal sinusitis,
toxic reactions,
MVOCs
Upper
respiratory tract,
skin, eyes
150-500 cfu/m3
The temperature measured in the indoor environments during monitoring ranged from
18°C to 37.8°C in the kitchens and living rooms while the average relative humidity levels ranged
from 20% to 75% in both the kitchens and living rooms. Temperature was noticed to be an
influencing factor for bacterial levels but not for fungal levels (table 19 and 20). Bacterial
activity is normally reduced at temperatures higher than 24°C (Tang, 2009) and bacteria also
requires more water activity than the fungi. On the contrary, in the case of fungi, temperature
may not be a limiting factor with most fungi growing at 10–35°C but humidity is still considered
a critical factor affecting fungal growth since dampness facilitates the growth of fungal spores
(Douwes et al., 1999; Nielsen et al., 1999). Relative humidity levels above 90% have been
reported to cause a 30% increase in fungal spore size. This increase in spore size can increase
the risk of deposition of spores in the respiratory tract, particularly bronchi by 20% (Reponen et
al., 1996). Moreover the transport of fungal spores is known to be more under the control of
Chapter Five Discussion
193
meteorological factors such as temperature, relative humidity and air flow. In fact the most
suitable RH levels for growth of fungi are 70% and above while the optimum temperature range
is between 30 to 40°C (Deguchi and Yoshizawa, 1996). However, variation still exists as similar
bacteria may behave differently at different temperatures and relative humidity levels. The
results of this research were in contrast with the above discussion as although temperature had a
direct but weak relation with bacteria, relative humidity exhibited no significant association
with bacterial and fungal levels.
Pakistan is lacking in baseline data for micro-floral composition of indoor micro-
environments. Previous studies conducted by Colbeck et al. (2008) and Nasir et al. (2012)
found that 55 to 93% of bioaerosols were respirable. They also reported higher levels of
bioaerosols in the indoor micro-environments of Pakistan than the current research except
maximum indoor bacterial levels which were almost similar to levels observed in this study.
A more recent study by Sidra et al. (2015) reported variations in bioaerosol levels in the indoor
micro-environments during activity and non-activity periods. It was noted that during the
performance of daily activities in the kitchens and living rooms, microbial levels were elevated
as compared to levels recorded when there was no work being carried out in both rooms.
Advanced sampling techniques need to be employed for monitoring indoor microflora.
Seasons have been documented by many researchers to significantly influence
pollutant levels in both the indoor and outdoor environments. Particulate matter and bioaerosol
levels were found to be affected by changing seasons in this study too. The current results
indicated highest levels of particulate matter during the winter season and lowest during the
summers as also observed by many other researchers such as Lee et al. (1997), He et al. (2001),
Li and Lin (2003), Ramachandran et al. (2003), Ye et al. (2003), Tiwari et al. (2011), Massey
Chapter Five Discussion
194
et al. (2012), and Massey et al. (2013). Ahmed (2007) also documented seasons to have a
marked impact upon bioaerosol levels. Likewise, Nasir et al. (2013) reported higher levels of
particulate matter in rural houses of Pakistan during the winter season while Frankel et al.
(2012) noticed elevated bioaerosol levels during spring and summer. Seasonal variability in
fungal levels was recorded by Adams et al. (2013) in both the ambient and indoor air. Recently,
Mentese et al. (2012) and Oh et al. (2015) documented the seasonal variability in levels of
particulate matter and bioaerosols in indoor microenvironments and observed higher levels of
PM during winters while bioaerosols levels were higher during summers. A possible
explanation for this outcome could be the reduced ventilation during the colder months as
windows and doors are generally kept closed throughout the day. Moreover, use of gas heaters
for space heating also generates considerable amounts of particulate matter. People prefer to
spend maximum time indoors and their activities may also influence indoor air quality.
Therefore the accumulation of particulate matter in the indoor environment is possible during
winters. On the other hand, during the summer season, doors and windows are kept open for
maximum part of the day with fans also being used thereby allowing maximum circulation of
air. As a result, the pollutant levels are diluted and easily dispersed. Nasir et al. (2013) also
suggested improved ventilation to reduce pollutant loads in the indoor environments.
Since Pakistan Environmental Protection Agency has not yet set any standards for the
permissible levels of PM2.5 and microbes in the indoor environment, WHO standards were
followed for PM2.5 while microbial levels were compared with standards set by different
countries. According to WHO air quality guidelines (AQG), the permissible levels of PM2.5
should not exceed 25µg/m³ in a 24-hour period while the annual mean should be 10 µg/m³
(WHO, 2006). The average PM2.5 levels documented in this study were 13 times higher than
Chapter Five Discussion
195
the WHO AQG limits in both the kitchens and living rooms of the selected sites. Meanwhile
the annual average WHO Interim Target-1 (IT-1) value for PM2.5 is 35 µg/m³ which were
exceeded by the documented levels in this study. Long term exposure to such high levels of
fine particulate matter can be detrimental for human health and thus need to be controlled.
It is difficult to set a limit for microbial contaminants in the air owing to the diversity of
microbial species and the health outcomes caused by each of them. The bioaerosol levels
obtained in this study were compared to obtain an insight into the current status of IAQ in the
representative households. The Swedish and Singaporean standards establish the limit to be not
more than 500 cfu/m3 for bacteria and 300 cfu/m3 for fungi in the indoor environments.
According to USA Occupational Safety and Health Administration (OSHA), air is polluted in
the presence of microbial load of 1000 cfu/m3 in the air while the American Industrial Hygiene
Association (AIHA) (2001) recommends the intensities of fungal spores to not surpass 500
cfu/m3 in inhabited structures. Referring to these standard values, it was apparent that the detected
microbial levels in this study were critically exceeding these levels. While the respiratory health
of the inhabitants was assessed through direct questioning and no grave health issue except for
dust allergy was perceived, monitoring of indoor air quality is essential to evaluate the exposure
risk of the occupants.
LIMITATIONS OF THE STUDY
There were certain limitations to this study. The monitoring of each sampling site was
conducted only once while it would have been more useful to monitor each site in all seasons
at different times of the year. This was a major drawback to the current study. Repeated
sampling however was not possible due to the noisy instruments for PM2.5 which were causing
disturbance to the occupants and people were reluctant to allow repeated measurements. Also
Chapter Five Discussion
196
the excessive load-shedding of electricity was an important constraint as it caused interruption
in continuous sampling of particulate matter. Moreover, passive sampling of bio-aerosols was
conducted as volumetric samplers were not available. Despite these limitations, the study was
an attempt to document the levels of two major pollutants of the indoor environments and to
obtain an understanding of the state of the residential micro-environments of Lahore, Pakistan.
Chapter Five Discussion
197
CONCLUSION
The presented dissertation focuses on the state of indoor air quality in residential micro-
environments of the metropolis of Lahore. The purpose was to document the intensities of two
major pollutants i.e. particulate matter and bioaerosols and the governing factors along with
their sources and external factors responsible for the obtained levels. Although there were
certain limitations to this study, it can be considered as first attempt to record the IAQ of urban
areas of Pakistan where no previous such data or study exists.
Monitoring of indoor air quality of thirty residences of Lahore revealed an alarming
situation as the observed parameters were greatly exceeding the established standards. Mean
PM2.5 levels were documented to be 13 times higher than the WHO air quality guidelines or
the Interim Target-1 while even the background levels were also 4-5 times higher. Bioaerosol
levels were also above the safety limits. There were a number of factors that described the
indoor air quality in the monitored sites. Seasonal variability had a prominent share as highest
levels were reported during the winter season when air change rate was minimum due to closed
windows and doors. Moreover gas heaters were also being used for space heating thereby
contributing significantly in increasing indoor PM2.5 levels. The mean PM2.5 levels dropped
during the spring season as ventilation practices improved and attained minimum levels in
summers as use of ceiling fans and open windows allowed maximum dilution of air. A slight
increase during the monsoon was observed with further increase during the fall.
Diurnal variations in particulate levels were also noted as throughout the day PM2.5 was
generated and/or re-suspended by a variety of domestic activities while lack of activities during
the night hours led to reduced PM levels. Ventilation was another noteworthy factor as a direct
correlation was observed between air exchange rates and PM levels in the living rooms. Such
Chapter Five Discussion
198
an association was observed to be lacking in the kitchens most probably due to the nature of
activities within which generated higher levels of particulate matter.
Major activities were identified which could cause substantial fluctuations in pollutant
levels indoors. Cooking (particularly frying) was the highest contributor while cleaning also
had a smaller share in the kitchens. In the living rooms, movement of occupants was
documented to influence indoor levels of fine particulate matter while cigarette smoking and
space heating (carried out at some sites) were also major contributors. The results were in
confirmation with many other studies associating the elevated levels of particulate matter in
residential settings resulting from various routine activities such as cooking, floor sweeping,
presence of people, smoking and space heating. The impact of household activities, ventilation
rates, and changing seasons upon the particulate matter concentrations in the indoor
environments was concluded to be substantial.
Since passive sampling of bioaerosols was conducted in comparison to real time
monitoring of PM2.5, it was challenging to quantify any association between PM levels and
indoor microflora. The micro-biota of the studied sites comprised of common constituent
species which were also reportedly known opportunistic pathogens. The colony forming units
per cubic meter of air were concluded to be higher than any established standards. Statistically
significant seasonal variation was observed for bioaerosol levels as well. Temperature had a
direct impact upon bacterial levels while relative humidity did not indicate any association
with microbial levels.
To sum up, the elevated levels of monitored parameters in the selected sites during the
course of this study pose a crucial situation. Since general public is unaware of the unhealthy
air they are taking in, there are little efforts to improve it. There is a dire need to monitor the
Chapter Five Discussion
199
indoor environments and to understand their potential sources so that suitable mitigation
measures may be introduced and a healthy environment may be maintained. In the absence of
any policy or guidelines for maintaing indoor air quality in Pakistan, it is absolutely
indispensable to focus on generating a baseline data and formulation of guidelines for
improvement of indoor air quality in both the urban and rural sectors of the country.
Chapter Five Discussion
200
RECOMMENDATIONS
The research undertaken highlights many aspects which need to be addressed at not
only individual level but most importantly at policy level to improve the living standards of
the general public and their health. The conclusion of the current study lead to proposal of the
following recommendations:
1. The first and most important step that needs to be taken is generation of a baseline data
regarding air quality of not only the residencies but the working indoor micro-
environments as well to assess the levels of various pollutants in the indoor micro-
environments and the potential hazards faced by the occupants.
2. There should be detailed and repeated measurements for background levels as well for
air quality of the rural and urban sites.
3. Since there are no standards set for the permissible limits of various indoor pollutants,
this aspect also needs to be covered. It is necessary to formulate some guidelines for
PM2.5 and bio-aerosols. Even the background levels monitored in this study are much
higher than the WHO limits of 25 µg/m³. It is therefore important to formulate and
implement some permissible standards to ensure a healthy environment.
4. Ventilation plays an important role in defining the air quality and there is a dire need
for the builders and construction authorities to consider maximum air exchange rate in
building designs to dilute the buildup of pollutants indoors.
5. Source appointment and strength of particulate emissions should be determined for
various indoor micro-environments so that a suitable intervention plan can be
implemented.
Chapter Five Discussion
201
6. Detailed and regular air quality monitoring of urban centres should be conducted as, in
Pakistan, many researchers have limited their focus on assessing the indoor air quality
of rural areas while urbanized areas have largely been ignored so far.
7. In view of the limited data on micro-flora of the indoor residential environments (only
three studies conducted so far) of Pakistan, it is highly recommended to carry detailed
sampling of bioaerosols in both rural and urban sectors. Moreover, sampling via
impaction or other active means should be preferred to obtain a clearer picture of the
bio-hazards we face.
8. To minimize the excessive humidity levels indoors, the exhaust fans in the kitchens,
living rooms and bathrooms venting outside can help to condense the bio aerosols
concentration.
9. Too many plants inside the micro environments can cause increased humidity therefore
increasing bio-flora, so there should be on check on the ornamentals plants to keep the
steadiness.
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Annexure-I
235
QUESTIONNAIRE
Name of respondant: _________________________________________________________
Address:___________________________________________________________________
___________________________________________________________________________
_________________________________________GPS:_____________________________
Contact #: _______________________ Occupation: _______________________________
Members of the family: _______
No. Members of
the family
Age Gender Occupation Time spent by each member
Outdoors In house In kitchen
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Annexure-I
236
Type of house: Owned Rented
Type of material used for construction: ___________________________________
Size of house: ___________________
Ventilation in:
Living room Kitchen
Area used for
ventilation
Area available
for ventilation
Total area of
the room
Area used for
ventilation
Area
available for
ventilation
Total area of
the room
Outside environment/surroundings:
Type of road:
Carpeted Uncarpeted Unrepaired
Source of aerosols from outside e.g. from drilling, maintenance works, sprays, grounds
(dust), factories etc.: ____________________________________________________
Indoors:
Kitchen: Temperature: ___________ Humidity: ________
Size: length: ________ width: __________ height: _________
Space for ventilation: _______________________________________________
Source/type of fuel used for cooking:
Sui gas LPG Kerosene oil Wood Other?
Maximum time spent in cooking:
Breakfast Lunch Dinner
Annexure-I
237
Eating habits:
Breakfast Lunch Dinner
Exhaust fan present: Yes No
Different items used in the house If Yes, then how often:
Weekly or daily Sometimes, as
required
Air fresheners used: No Yes
Leakage of gas: No Yes
Cleaning solvents
used:
No Yes
Type of floor:
Cemented Bricked tiled
Type of windows:
With wire gauze Without wire gauze
Living room: Temperature: ___________ Humidity: ________
Size: length: ________ width: __________ height: ____________
Space for ventilation: ____________________________________________________
Different items used in the house If Yes, then how often:
Weekly or daily Sometimes, as
required
Air fresheners: No Yes
Cleaning solvents
used:
No Yes
Annexure-I
238
Type of floor:
Cemented Bricked Tiled
Carpeted Rugs/ floor mats Nothing
Type of windows:
With wire gauze Without wire gauze
Rest of the house:
Cleaning / dusting of house
Daily Weekly Irregular
Different items used in the house If Yes, then how often:
Weekly or daily Sometimes, as
required
Air fresheners
perfumes, and body
sprays:
No Yes
Cleaning solvents,
paints, insecticides,
coils, etc.
No Yes
Air conditioners/
heaters used:
No Yes
Use of fertilizers/
pesticides on plants:
No Yes
Computers, printers present: Yes No
Presence of termites: Yes No
Annexure-I
239
Presence of lawn/ potted plants: Yes No
Indoors plants: Yes No
Pet animals: Yes No
Wooden paneling (source of formaldehyde): Yes No
Type of floor:
Cemented Bricked Tiled
Carpeted Rugs/ floor mats Nothing
Type of windows:
With wire gauze Without wire gauze
Children play indoors or outdoors: _________________________________________
Games played indoors: _________________________________________________
Mode of transport used:
Car Motorcycle Cycle
Health issues:
Daily walk/ exercise: Yes No
No. of smokers (if any) in house: _______
Smoking within house or outside? ________
Any member of the house suffering from any chronic ailment: _____________________
Vaccination of the children: Yes No
Annexure-I
240
Health Problems Details
Respiratory problems
(Asthma, infections, labored
breathing, severe lung
disease etc.)
Allergy (due to dust or
other reasons)
Headaches, vomiting,
nausea, rashes etc.
Irritation of mucous
membranes of eyes
Hypertension
Any other related problem
Annexure-II
241
Maximum and minimum air exchange rate at each sampling site
Figure 1: Maximum ACH in kitchen of A1
Figure 2: Minimum ACH in Kitchen of A1
y = -7.9069x + 8.1408
R² = 0.993
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -4.1361x + 7.9966
R² = 0.9897
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
242
Figure 3: Maximum ACH in living room of A1
Figure 4: Minimum ACH in living room of A1
y = -6.7835x + 8.4088
R² = 0.9824
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
y = -3.5222x + 8.1551
R² = 0.9937
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
243
Figure 5: Maximum ACH in kitchen of A2
Figure 6: Minimum ACH in kitchen of A2
y = -6.2765x + 8.2856
R² = 0.9611
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (hours)
ACH
y = -3.1898x + 8.365
R² = 0.9641
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
244
Figure 7: Maximum ACH in living room of A2
Figure 8: Minimum ACH in living room of A2
y = -3.5716x + 8.2285
R² = 0.9685
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -3.0016x + 8.3506
R² = 0.9661
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
245
Figure 9: Air Change rate per hour in Kitchen (Semi-open) in A3
Figure 10: Maximum ACH in living room of A3
y = -11.077x + 8.1112
R² = 0.9891
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
Ln (
CO
2)
Time (Hours)
ACH
y = -3.8306x + 8.3124
R² = 0.9783
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
246
Figure 11: Minimum ACH in living room of A3
Figure 12: Maximum ACH in kitchen of A4
y = -1.9671x + 8.1628
R² = 0.942
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -4.9631x + 8.1958
R² = 0.8885
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
247
Figure 13: Minimum ACH in kitchen of A4
Figure 14: Maximum ACH in living room of A4
y = -3.2017x + 8.0593
R² = 0.9787
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
y = -3.5076x + 8.3994
R² = 0.9584
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
248
Figure 15: Minimum ACH in living room of A4
Figure 16: Maximum ACH in kitchen of A5
y = -1.9193x + 8.3623
R² = 0.9286
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Ln (
CO
2)
Time (Hours)
ACH
y = -5.3551x + 8.2601
R² = 0.9615
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
249
Figure 17: Minimum ACH in kitchen of A5
Figure 18: Maximum ACH in living room of A5
y = -2.7939x + 7.9605
R² = 0.9949
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
8
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -7.4018x + 8.4597
R² = 0.9785
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
250
Figure 19: Minimum ACH in living room of A5
Figure 20: Maximum ACH in kitchen of A6
y = -2.3342x + 8.2098
R² = 0.9415
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -4.8212x + 8.0987
R² = 0.9947
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
251
Figure 21: Minimum ACH in kitchen of A6
Figure 22: Maximum ACH in living room of A6
y = -3.2047x + 8.2588
R² = 0.9841
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -6.0815x + 8.1208
R² = 0.9789
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
252
Figure 23: Minimum ACH in living room of A6
Figure 24: ACH in kitchen of A7 (Semi-open kitchen)
y = -2.4888x + 8.206
R² = 0.9466
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -11.567x + 8.521
R² = 0.9992
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
253
Figure 25: Maximum ACH in living room of A7
Figure 26: Minimum ACH in living room of A7
y = -4.7517x + 8.287
R² = 0.958
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
y = -2.3275x + 8.2805
R² = 0.9568
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
254
Figure 27: Maximum ACH in kitchen of A8
Figure 28: Minimum ACH in kitchen of A8
y = -2.6797x + 8.0516
R² = 0.9871
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -2.6749x + 8.1059
R² = 0.9667
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
255
Figure 29: Maximum ACH in living room of A8
Figure 30: Minimum ACH in living room of A8
y = -5.5495x + 8.0564
R² = 0.9727
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
y = -3.8028x + 8.084
R² = 0.9571
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
256
Figure 31: Maximum ACH in kitchen of A9
Figure 32: Minimum ACH in kitchen of A9
y = -8.2015x + 8.3994
R² = 0.975
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -3.7501x + 8.1449
R² = 0.9698
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
257
Figure 33: Maximum ACH in living room of A9
Figure 34: Minimum ACH in living room of A9
y = -5.4744x + 8.518
R² = 0.9795
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
y = -2.86x + 8.2838
R² = 0.9428
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
258
Figure 35: ACH in semi-open kitchen of A10
Figure 36: Maximum ACH in living room of A10
y = -11.679x + 8.0647
R² = 0.9996
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
Ln (
CO
2)
Time (Hours)
ACH
y = -5.3389x + 8.6804
R² = 0.9618
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
259
Figure 37: Minimum ACH in living room of A10
Figure 38: Maximum ACH in kitchen of B1
y = -2.7704x + 8.1911
R² = 0.9854
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -8.3944x + 8.1973
R² = 0.9669
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25
Ln (
CO
2)
Time (hours)
ACH
Annexure-II
260
Figure 39: Minimum ACH in kitchen of B1
Figure 40: Maximum ACH in living room of B1
y = -4.9872x + 8.1923
R² = 0.956
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
y = -6.5084x + 8.2026
R² = 0.9811
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
ln (
CO
2)
Time (Hours)
ACH
Annexure-II
261
Figure 41: Minimum ACH in living room of B1
Figure 42: Maximum ACH in kitchen of B2
y = -2.6519x + 8.0153
R² = 0.9812
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -8.3247x + 8.4684
R² = 0.9531
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
262
Figure 43: Minimum ACH in kitchen of B2
Figure 44: Maximum ACH in living room of B2
y = -4.7468x + 8.4521
R² = 0.9665
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
y = -5.0387x + 8.0359
R² = 0.9842
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln(C
O2)
Time (Hours)
ACH
Annexure-II
263
Figure 45: Minimum ACH in living room of B2
Figure 46: Maximum ACH in kitchen of B3
y = -3.4382x + 8.2513
R² = 0.9717
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -5.255x + 8.3788
R² = 0.9827
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
264
Figure 47: Minimum ACH in kitchen of B3
Figure 48: Maximum ACH in living room of B3
y = -3.9477x + 8.4057
R² = 0.9653
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
y = -5.6596x + 8.0909
R² = 0.9337
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
265
Figure 49: Minimum ACH in living room of B3
Figure 50: Maximum ACH in kitchen of B4
y = -2.43x + 7.6678
R² = 0.9813
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
y = -6.6962x + 8.7511
R² = 0.9909
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
266
Figure 51: Minimum ACH in kitchen of B4
Figure 52: Maximum ACH in living room of B4
y = -4.2373x + 8.3382
R² = 0.9689
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
y = -5.2986x + 7.8673
R² = 0.9803
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
267
Figure 53: Minimum ACH in living room of B4
Figure 54: Maximum ACH in kitchen of B5
y = -2.7536x + 8.2647
R² = 0.915
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -3.353x + 8.2156
R² = 0.9827
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
268
Figure 55: Minimum ACH in kitchen of B5
Figure 56: Maximum ACH in living room of B5
y = -6.6034x + 8.2944
R² = 0.978
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -3.7929x + 8.7279
R² = 0.9127
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
269
Figure 57: Minimum ACH in living room of B5
Figure 58: Maximum ACH in kitchen of B6
y = -2.3245x + 8.5535
R² = 0.9583
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Ln (
CO
2)
Time (Hours)
ACH
y = -7.6766x + 8.1664
R² = 0.9986
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
8
0 0.05 0.1 0.15 0.2 0.25
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
270
Figure 59: Minimum ACH in kitchen of B6
Figure 60: Maximum ACH in living room of B6
y = -3.0793x + 8.0226
R² = 0.9854
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -5.4196x + 8.422
R² = 0.9758
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
271
Figure 61: Minimum ACH in living room of B6
Figure 62: ACH in kitchen (semi-open) of B7
y = -3.8696x + 8.2778
R² = 0.9832
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
y = -5.6395x + 8.0652
R² = 0.9974
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
8
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
272
Figure 63: Maximum ACH in living room of B7
Figure 64: Minimum ACH in living room of B7
y = -5.045x + 8.2159
R² = 0.9979
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
y = -3.2339x + 8.1495
R² = 0.9514
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
273
Figure 65: ACH in semi-open kitchen of B8
Figure 66: Maximum ACH in living room of B8
y = -14.973x + 8.1329
R² = 0.8141
0
1
2
3
4
5
6
7
8
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
Ln (
CO
2)
Time (Hours)
ACH
y = -6.5732x + 8.596
R² = 0.954
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
274
Figure 67: Minimum ACH in living room of B8
Figure 68: Maximum ACH in kitchen of B9
y = -2.0385x + 8.3153
R² = 0.9767
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Ln (
CO
2)
Time (Hours)
ACH
y = -4.9018x + 8.2489
R² = 0.9736
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
275
Figure 69: Minimum ACH in kitchen of B9
Figure 70: Maximum ACH in living room of B9
y = -2.6257x + 8.2797
R² = 0.9619
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -5.4952x + 8.2582
R² = 0.9684
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
276
Figure 71: Minimum ACH in living room of B9
Figure 72: Maximum ACH in kitchen of B10
y = -2.9839x + 8.2991
R² = 0.977
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -7.5151x + 8.1602
R² = 0.9949
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
277
Figure 73: Minimum ACH in kitchen of B10
Figure 74: Maximum ACH in living room of B10
y = -6.6874x + 8.1857
R² = 0.9931
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
y = -2.8049x + 8.3831
R² = 0.9432
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
278
Figure 75: Minimum ACH in living room of B10
Figure 76: Maximum ACH in kitchen of C1
y = -2.4325x + 8.1857
R² = 0.9818
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -6.0065x + 8.009
R² = 0.9786
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
279
Figure 77: Minimum ACH in kitchen of C1
Figure 78: Maximum ACH in living room of C1
y = -3.6443x + 8.1467
R² = 0.9567
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
y = -5.3477x + 8.4504
R² = 0.9593
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
280
Figure 79: Minimum ACH in living room of C1
Figure 80: Maximum ACH in kitchen of C2
y = -3.7812x + 8.2261
R² = 0.9884
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
y = -5.1207x + 8.3561
R² = 0.9689
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
281
Figure 81: Minimum ACH in kitchen of C2
Figure 82: Maximum ACH in living room of C2
y = -2.9247x + 8.1209
R² = 0.9903
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
y = -5.4842x + 8.1656
R² = 0.9746
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
ACH
Annexure-II
282
Figure 83: Minimum ACH in living room of C2
Figure 84: Maximum ACH in kitchen of C3
y = -4.062x + 8.2934
R² = 0.9012
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
y = -4.6801x + 8.3881
R² = 0.9563
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
283
Figure 85: Minimum ACH in kitchen of C3
Figure 86: Maximum ACH in living room of C3
y = -2.4751x + 8.0932
R² = 0.9845
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Times (Hours)
ACH
y = -6.6689x + 8.0059
R² = 0.9571
6.6
6.8
7
7.2
7.4
7.6
7.8
0 0.05 0.1 0.15 0.2 0.25
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
284
Figure 87: Minimum ACH in living room of C3
Figure 88: Maximum ACH in kitchen of C4
y = -2.413x + 8.2684
R² = 0.8955
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -6.7427x + 8.6079
R² = 0.9684
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
285
Figure 89: Minimum ACH in kitchen of C4
Figure 90: Maximum ACH in living room of C4
y = -2.4962x + 8.3356
R² = 0.9369
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ln (
CO
2)
Time (Hours)
ACH
y = -5.1335x + 8.392
R² = 0.9227
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
286
Figure 91: Minimum ACH in living room of C4
Figure 92: ACH in kitchen of C5
y = -3.2015x + 8.2193
R² = 0.9062
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -10.216x + 8.3236
R² = 0.9721
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
287
Figure 93: Maximum ACH in living room of C5
Figure 94: Minimum ACH in living room of C5
y = -5.1111x + 8.2085
R² = 0.9638
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
y = -2.7587x + 7.9263
R² = 0.985
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
288
Figure 95: Maximum ACH in kitchen of C6
Figure 96: Minimum ACH in kitchen of C6
y = -6.8025x + 8.3626
R² = 0.9814
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -3.9065x + 8.4032
R² = 0.9631
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
289
Figure 97: Maximum ACH in living room of C6
Figure 98: Minimum ACH in living room of C6
y = -8.1486x + 8.5696
R² = 0.9713
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -3.3347x + 8.1146
R² = 0.9906
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
290
Figure 99: Maximum ACH in kitchen of C7
Figure 100: Minimum ACH in kitchen of C7
y = -14.507x + 8.6033
R² = 0.9977
0
1
2
3
4
5
6
7
8
9
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
Ln (
CO
2)
Time (Hours)
ACH
y = -2.7614x + 7.2088
R² = 0.8893
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
7
7.1
7.2
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
291
Figure 101: Maximum ACH in living room of C7
Figure 102: Minimum ACH in living room of C7
y = -5.9104x + 8.1498
R² = 0.8414
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -3.3983x + 7.94
R² = 0.9279
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
292
Figure 103: Maximum ACH in kitchen of C8
Figure 104: Minimum ACH in kitchen of C8
y = -11.019x + 8.8204
R² = 0.9436
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25
Ln (
CO
2)
Time (Hours)
ACH
y = -3.4409x + 8.308
R² = 0.9846
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
293
Figure 105: Maximum ACH in living room of C8
Figure 106: Minimum ACH in living room of C8
y = -9.122x + 8.4411
R² = 0.9952
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -3.2858x + 8.2802
R² = 0.9606
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
294
Figure 107: Maximum ACH in kitchen of C9
Figure 108: Minimum ACH in kitchen of C9
y = -6.783x + 8.1766
R² = 0.9976
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3
Ln (
CO
2)
Time (Hours)
ACH
y = -2.9536x + 8.0779
R² = 0.9672
6.4
6.6
6.8
7
7.2
7.4
7.6
7.8
8
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
295
Figure 109: Maximum ACH in living room of C9
Figure 110: Minimum ACH in living room of C9
y = -4.9648x + 8.7169
R² = 0.8735
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Ln (
CO
2)
Time (Hours)
ACH
y = -2.3444x + 8.395
R² = 0.9481
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
296
Figure 111: Maximum ACH in kitchen of C10
Figure 112: Minimum ACH in kitchen of C10
y = -3.7151x + 8.2334
R² = 0.9724
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
y = -5.4048x + 8.1921
R² = 0.9645
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Ln (
CO
2)
Time (Hours)
ACH
Annexure-II
297
Figure 113: Maximum ACH in living room of C10
Figure 114: Minimum ACH in living room of C10
y = -5.9736x + 8.5281
R² = 0.9387
0
1
2
3
4
5
6
7
8
9
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Ln (
CO
2)
Time (Hours)
ACH
y = -3.4555x + 8.3589
R² = 0.9623
0
1
2
3
4
5
6
7
8
9
0 0.1 0.2 0.3 0.4 0.5 0.6
Ln (
CO
2)
Time (Hours)
ACH
Annexure-III
298
Annual Trend of Ambient Air Quality of Lahore
NO NO2 NOx CO SO2 O3 PM2.5
Wind
Speed Wind Dir Temp RH Radiation
Annual Average µg/m³ µg/m³ µg/m³ mg/m³ µg/m³ µg/m³ µg/m³ m/s degrees degC % W/m2
2008 19.92 35.59 55.51 1.23 52.91 47.04 123.28 1.71 177.61 27.52 64.59 188.56
2009 18.35 37.72 56.06 1.48 67.51 49.49 128.76 1.68 204.03 26.25 60.68 173.33
2010 20.52 39.25 59.77 2.33 69.25 59.28 135.88 1.58 214.25 27.86 59.24 185.69
NEQS
(Annual Average) 40 40 - 5 80 130 25
Remarks: Inhalable (Respirable) Dust PM2.5 was found almost 5 times higher than National Environmental Quality Standard
while oxides of Nitrogen (NO2) is also touching the maximum value.
Muhammad Nadeem
Research Assistant
ENVIRONMENTARIAM
ENVIRONMENT PROTECTION DEPARTMENT
GOVERNMENT OF THE PUNJAB
NATIONAL HOCKEY STADIUM, FEROZPUR
ROAD, LAHORE
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299
INSTALLATION OF INSTRUMENTS AT THE SAMPLING SITES
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