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PTDC/DTP-SAP/1522/2012

INDOOR BIOLOGICAL AGENTS: EVALUATION OF

PRIMARY SCHOOLS ENVIRONMENTS

Lívia Vanessa Ferreira de AguiarWork under the supervision of:

- Professor João Paulo Teixeira

- Professor Celina Pinto Leão18th February 2016

Master Thesis for MSc Degree in Human Engineering

Guimarães, Portugal

INTRODUCTION

8th most importantrisk factor for thedevelopment ofdisease

4.3 million deathsannualy

WHOMain 5 environmental risksto public health

Indoor levels ofpollutants can be 2 to 5 times higherthan outdoor levels

US EPA

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INTRODUCTION

The results of this study are part of ARIA Project, performed between 2013 and 2015.

Explore associations between various exposures that children experience in their indoor environments (specifically their homes and primary schools).

Investigate the associated respiratory and allergic related health effects in 1600 children.

The targeted health issues were allergy, asthma and respiratory symptoms.

PROJECT MAIN OBJECTIVES

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STUDY RELEVANCE

Over

crowding

Highincidence ofinfectiousdiseases

Reducedbudgets SCHOOLS

Inadequatemaintenance of school

buildings

Although home environment has been the focus of research studies…

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Susceptible group due to their particularly vulnerability to the development ofrespiratory diseases.

Time they spend inside classrooms

Indoor Air Qualitystudies

STUDY RELEVANCE

Impact on child’s exposure to pollutants

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OBJECTIVES

To evaluate children’s exposure to indoor air biologicalpollutants in primary schools of Porto, Portugal

To evaluate children’s exposure to indoor air biologicalpollutants in primary schools of Porto, Portugal

To assessand quantifybacteria, fungiand endotoxinsconcentrations, in 20 primary

schools, and to compare theattained resultswith national/ internationalguidelines

To assess theimpact ofoutdoor

bacteria andfungi

concentrationsin indoor air

To identifythe main

fungi genera/ speciespresent

To investigate

the influence ofCO2, T and RH concerning the

biologicalpollutants

concentrations

To determine if the

concentrationsof bacteria, fungi andendotoxins

varies according witheach other’s

concentrations

To investigateif primaryschools’

buildings/ classroom

characteristicsand occupants

activitiesinterfere with

indoor airbiological

contaminationlevels

To suggestintervention

and/orimprovementmeasures for a better IAQ in primaryschools

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METHODOLOGY

Cross-sectional study

20 schools, with the highest number of students and considered representative of the

building stock were invited to participate in this study and all of them agreed.

In each school, four classrooms of 3rd and/or 4th grades were selected, among classrooms with

similar conditions and considered to be representative of the school building.

Classrooms should have high density of occupation and full weekly occupation time by the

same class.

A total of 71 classrooms were assessed,

comprising a universe of 1523 students attending daily classes.Figure 1 - Geographical distribution of the selected

20 public primary schools.

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METHODOLOGY

Two heating season periods:

January to April 2014 - 10 schools, 35 classrooms

October 2014 to January 2015 - 10 schools, 36 classrooms

Normal activities and under representative conditions of occupancy of the classrooms

CROSS-SECTIONAL STUDY OF CHILDREN’S INDOOR AIR EXPOSURE

Enclosedenvironments

Studied parameters:

Building and classroom characteristics

standardized validated checklist [SINPHONIE]

Biological parameters

total bacteria count and fungi count and

identification

endotoxin concentration

Chemical parameters Carbon Dioxide [CO2]

Physical parameters Temperature [T] and Relative Humidity [RH]

Figure 2 - TSI 7545 IAQ-CALC

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TSABacteria

MEAFungi

TSA

MEA

MAS100, 250 Liters of air volume, 100 Liters per minute (L/min) rate

Duplicates

Four field blanks, two sterility blanks, one positive and one negative control per

culture medium, per day

Outdoor samples were also collected in each campaign, for comparison to

the indoor measurements

TSA

MEA

37±1ºC

25±3ºC

48±3 h

72±3 h

Fungal colonies identification: phenotypic characteristics and standard mycological procedures based on their

micro and macro-morphological characteristics

Quantification: naked eye count

METHODOLOGY

RESULTS: CFU/M3

BACTERIA & FUNGI ASSESSMENT

Figure 3 - Microbiological air impactor (Merck Air Sampler, MAS-100).

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SAMPLING

Portable high flow pump [2 L/min flow]

Button aerosol sampler with a 25 mm glass microfibre filter [GFA]

4 hour sampling

All materials used for sampling were treated at 180ºC for at least 4 hours prior to sampling.

Samples were kept frozen at -20ºC until analysis.

METHODOLOGY

RESULTS: EU/M3

ENDOTOXINS ASSESSMENT

ANALYSIS

EXTRACTION

Sample filters were eluted in 5 mL extraction solution.

Rocked vigorously for 1h at room temperature on a

horizontal shaker.

After 10 minutes of centrifugation at 1000 g, total

supernatant per sample was collected and analyzed.

QUANTIFICATION

LAL Kinetic-QCLTM [Lonza®] following manufacturer’s

guidelines.

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RESEARCH QUESTIONS

Do indoor levels of bacteria, fungi and endotoxins in primary schools exceed the respectivenational and international reference values?

Is outdoor air the major influence on indoor air biological levels at schools?

What are the predominant fungi genera/species identified in indoor environments of primary schools?

Indoor air biological parameters are influenced by T or RH of the indoor environment? And what about CO2?

Is there any relationship between the bacteria, fungi and endotoxin concentrations foundindoors?

Are indoor biological concentrations affected by building and/or classrooms characteristics, including occupancy?

How can we improve IAQ of primary schools, regarding indoor biological parameters?

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RESEARCH QUESTIONS

Do indoor levels of bacteria, fungi and endotoxins in primary schoolsexceed the respective national and international reference values?


What are the predominant fungi genera/species identified in indoor environments ofprimary schools?

Indoor air biological parameters are influenced by T or RH of the indoor environment? Andwhat about CO2?

Is there any relationship between the bacteria, fungi and endotoxin concentrations foundindoors?

Are indoor biological concentrations affected by building and/or classroomscharacteristics, including occupancy?

How can we improve IAQ of primary schools, regarding indoor biological parameters?12

RESULTS

Bacteria levels 2 to 9 times higher than the established limit value

40 x

66 x

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RESULTS

Figure 4 - Mean endotoxins concentrations (EU/m3) by primary school

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RESEARCH QUESTIONS


Is outdoor air the major influence on indoor air biological levels atschools?



Is there any relationship between the bacteria, fungi and endotoxin concentrations found indoors?



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RESULTS

Figure 5 - Mean indoor and outdoor bacteria and fungi concentrations (CFU/m3)

Significant differencesfound between indoorand outdoor bacteria

as well as fungiconcentrations

For bacteria, I/O ratios higher than 1 were observed in all schools.

For fungi, 5 schools had I/O ratios below than 1.

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RESEARCH QUESTIONS








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RESULTS

Penicillium sp.

Cladosporium sp.

INDOOROUTDOOR

Figure 6 - Mean percentage of fungi genera/species identified indoors.

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RESEARCH QUESTIONS




Indoor air biological parameters are influenced by T or RH of theindoor environment? And what about CO2?




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RESULTS

Figure 8 - Indoor concentrations of Bacteria and CO2, by SchoolFigure 9 - Indoor concentrations of Fungi and RH levels, by School

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RESEARCH QUESTIONS








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RESULTS

Figure 10 - Indoor concentrations of Bacteria and Fungi, by School

Figure 11 - Indoor concentrations of Bacteria and Endotoxins, by School

Figure 12 - Indoor concentrations of Fungi and Endotoxins, by School

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RESEARCH QUESTIONS






Are indoor biological concentrations affected by building and/orclassrooms characteristics, including occupancy?


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RESULTS

Endotoxins concentrations were

higher in buildings with:

single walls

without roof leaking

Endotoxins concentrations & Year of

building refurbishment:

the more recently the intervention was

made, the higher were concentrations of

endotoxins in indoor air.

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RESULTS

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RESEARCH QUESTIONS






Are indoor biological concentrations affected by building and/or classroomscharacteristics, including occupancy?


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IMPROVEMENT MEASURES

Strategies of source control

Carefully studythe location of

future buildings andits relationshipwith outdoor environment

Proper design and

construction ofschool

buildings andselection of

clean materials

Proper level ofcontinuosthermal

insulation ofthe building

avoidingcondensationsand dampness

indoors

Decoupling ofheating/ cooling

functions fromthe ventilation

system

Definition andenforcement of

limits for maximumpermittedoccupationdensities in classrooms; definition ofclasses and

breaks durations; establish

routines ofcleaning andmaintenanceprocedures

Periodical monitoring of

IAQ and healthparameters in

schools

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IMPROVEMENT MEASURES

VentilationMeasures

Portuguese guidelines suggests a ventilation rate of 24 m3/(hour.person)for classrooms

Admission of outside air should be explored, unless confirmed outdoorsources or pollution are located nearby the school

Naturally ventilate classrooms through windows opening before the schoolday starts, during each classroom break and also after cleaning procedures

Implementation of tilting windows and the introduction of ventilation grillsin windows frames

Implementation of mechanical system when natural ventilation is notsufficient to reach the desired ventilation rate, preferably with intake of freshair, and attention must be paid to its regular inspection and maintenance

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CONCLUSIONS

MAIN FINDINGS:

Mean indoor bacteria concentrations were above national limit values

in all of the evaluated Porto primary schools, from 2 to 9 times higher.

High numberof occupants

Lack ofventilation

Active behavioralpattern ofchildren

School buildingand classroomscharacteristics

Endotoxins concentrations were below the recommended value of 50 EU/m3 in all primary schools

evaluated.

Fungi indoor levels were above the reference value in 75% of the schools and overall indoors levels registered

a 3-fold increase comparing with outdoor values.

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CONCLUSIONS

MAIN FINDINGS:

Overall I/O ratios of 9 and 3 for bacteria and fungi concentrations, respectively,

demonstrated that indoor sources are the major influence on biological levels at schools.

Penicillium sp. and Cladosporium sp. were the prevalent fungi species found indoors and outdoors of

primary schools. Both genera are considered common in indoor environments according with national legislation

and several studies available in current literature.

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CONCLUSIONS

MAIN FINDINGS:

Bacteria and endotoxins concentrations were higher with higher levels of RH and CO2.

Fungi concentrations did not fluctuate with T, RH or CO2 …

But did positively relate with bacteria concentrations: higher values of fungi

corresponded to higher levels of bacteria.

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CONCLUSIONS

MAIN FINDINGS:

Contrarily to what was expected, bacteria and endotoxins concentrations

showed no relation between them.

Endotoxins were the studied biological parameter that showed to be more

affected by school building and classrooms characteristics.

To improve IAQ of primary schools, strategies of source control should be adopted as these are the most

consistent and efficient for the prevention of adverse health consequences to children in schools, like the

development and aggravation of asthma, allergies and respiratory symptoms.

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FURTHER DEVELOPMENTS

Assess indoor environment in a larger sample of primary schools, in an integrated IAQ audit

Perform IAQ audits in the same classrooms of primary schools along all school year

Extend this IAQ audit to the indoor environment of children’s homes

Perform endotoxin assessment in rural and urban environments, with and without farming activities

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ACKNOWLEDGMENTS

PTDC/DTP-SAP/1522/2012

[email protected]

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