CHAPTER - II

AMBIENT AIR QUALITY IN MYSORE

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Introduction:

On December 5, 1952, a toxic mix of dense fog and sooty black coal smoke descended on

Londoners. Everyone in London walked blind for the next four days. By the time the

smog blew off on Dec. 9, thousands of Londoners were dead, and thousands more were

about to die. Roads were littered with abandoned cars. Midday concerts were cancelled

due to total darkness. Cattle in the city's Smithfield market were killed and thrown away

before they could be slaughtered and sold — their lungs were black. When the

ambulances stopped running, thousands of gasping Londoners walked through the smog

to the city's hospitals. The lips of the dying were blue. Heavy smoke and chronic

exposure to pollution had already weakened the lungs of those who fell ill during the

smog. Particulates and acids in the killer fog finished the job by triggering massive

inflammations. In essence, the dead had suffocated. According a study in the journal

Environmental Health Perspectives, 12,000 may have been killed by the great smog.

It remains the deadliest environmental episode in recorded history. The killer fog changed

the way the world looks at pollution. Before the incident, people in cities tended to accept

pollution as a part of life. Afterward, they fought to limit the poisonous side effects of the

industrial age.

The air we breathe is a mixture of gases and small solid and liquid particles. Some

substances come from natural sources while others are caused by human activities such as

our use of motor vehicles, domestic activities, industry and business. Air pollution occurs

when the air contains substances in quantities that could harm the comfort or health of

humans and animals, or could damage plants and materials. These substances are called

air pollutants and can be either particles, liquids or gaseous in nature (Alias et al., 2007).

Keeping the air quality acceptable has become an important task for decision makers as

well as for non-governmental organizations. Particulate matter and gaseous emissions of

pollutant emission from industries and auto exhausts are responsible for rising discomfort,

increasing airway diseases and deterioration of artistic and cultural patrimony in urban

centers (Mukunda Rao et al., 2003).

As many cities around the world become more congested, concerns increase over the

level of urban air pollution being generated and in particular its impact on localized

human health effects such as asthma or bronchitis. The more this relationship is

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understood, the better chance there is of controlling and ultimately minimizing such

effects. In the majority of the developed world, legislation has already been introduced to

the extent that local authorities are required by law to conduct regular Local Air Quality

Reviews of key urban pollutants such as SO2, NOx or Ozone produced by industrial

activity and/or road transport ( Ghanem et al., 2004).

In most European countries, industrialization and high volumes of traffic mean that

anthropogenic sources predominate, especially in urban areas, and sources of

anthropogenic particles are similar throughout Europe. The most significant of these are

traffic, power plants, combustion sources (industrial and residential), industrial fugitive

dust, loading/unloading of bulk goods, mining activities, human started forest fires and in

some local cases, non-combustion sources such as building construction and quarrying.

The main natural sources of airborne particulates in Europe are sea spray and soil

resuspension by the wind. In addition, in the Mediterranean basin and the Atlantic

archipelagos (eg Canaries, Azores), Saharan dust and volcano emissions can also be

important natural sources of particles.

In the UK, local authorities are now required to improve air quality in their respective

area. In most urban areas, emissions from traffic are a major contributor of harmful

pollutants such as nitrogen oxides (NOx) and particulate matter (PM) (Lim Ling et al.,

2005).

In India, pollution has become a great topic of debate at all levels and especially the air

pollution because of the enhanced anthropogenic activities such as burning fossil fuels,

i.e. natural gas, coal and oil- to power industrial processes and motor vehicles. Among the

harmful chemical compounds, this burning puts into the atmosphere, are carbon d ioxide

(CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulphur dioxide (SO2), and tiny

solid particles including lead from gasoline additives called particulates (Goyal and

Sidhartha, 2003 ).

In India, outdoor air pollution is restricted mostly to urban areas, where automobiles are

the major contributors, and to a few other areas with a concentration of industries and

thermal power plants. Apart from rapid industrialization, urbanization has resulted in the

emergence of industrial centers without a corresponding growth in civic amenities and

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pollution control mechanisms. In most of the 23 Indian cities with a million-plus

population, air pollution levels exceed World Health Organization’s (WHO)

recommended health standards. In every city, the levels are getting worse because of

rapid industrialization, growing number of vehicles, energy consumption, and burning of

wastes. Several cities face severe air pollution problems, with annual average levels of

total suspended particulates (TSP) at least three times as high as the WHO standards. A

study conducted by the World Bank indicates premature deaths of people in Delhi owing

to high levels of air pollution (Review of air quality management system in India).

Air Pollutants

The air pollutants can be classified as primary or secondary pollutants. The primary air

pollutants are harmful chemicals, which directly enter the air due to natural events of

human activities. A secondary air pollutant is a harmful chemical produced in the air due

to chemical reaction between two or more components. That is a primary pollutant

combine with some component of the atmosphere to produce a secondary pollutant (Naik,

2005).

Among the most common and poisonous air pollutants are sulphur dioxide (SO2), formed

when fossil fuels such as coal, gas and oil are used for power generation; suspended

particulate matter (SPM), solid and liquid particles emitted from numerous man-made and

natural sources such as industrial dust, volcanic eruptions and diesel-powered vehicles;

and nitrogen oxides (NOx), from natural sources such as lightning and fires (Ahmed

Hayatham, 1999).

The Central Pollution Control Board initiated National Ambient Air Quality Monitoring

(NAAQM) programme in the year 1984 with 7 stations at Agra and Anpara. Subsequently

in 1998-99 the programme was renamed as National Air Monitoring Programme

(NAMP). The number of monitoring stations under NAMP has increased, steadily, to 295

by 2000-01 covering 98 cities/towns in 29 States and 3 Union Territories of the country.

Under NAMP, four air pollutants viz., Sulphur Dioxide (SO2), Oxides of Nitrogen as

NO2, Total Suspended Particulate (TSP) and Respirable Suspended Particulate Matter

(RSPM/PM10), have been identified for regular monitoring at all the locations (CPCB,

2002).

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1. Sulphur dioxide:

It is a colorless gas with a pungent and suffocating odour. The gas is produced by the

combustion of fossil fuels (Naik, 2005). Sources include industrial activities such as

flaring at oil and gas facilities and diesel power generation, commercial and home heating

and vehicle emissions. The amount of SO2 emitted is directly related to the sulphur

content of the fuel (Air Quality Monitoring Network, 2008).

2. Nitrogen oxides (NOx):

NOx represents the sum of the various nitrogen gases found in the air, of which Nitric

Oxide (NO) and Nitrogen Dioxide (NO2) are the dominant forms. The emission sources

are varied but tend to result from high temperature combustion of fuel for industrial

activities, commercial and residential heating, and vehic le use. Forest fires can be a large

natural source of NOx (Air Quality Monitoring Network, 2008).

3. Total suspended particulate (TSP):

TSP refers to particles ranging in size from the smallest to a generally accepted upper

limit of 50-100 microns in diameter. TSP is dominated by the larger sized particles

commonly referred to as “dust” and is associated with aesthetic and environmental

impacts such as soiling of materials or smothering of vegetation (Air Quality Monitoring

Network, 2008). The entire domain of particulate matter is known as Total Suspended

Particulate, TSP (IPCC, 2001). This includes all airborne solid and liquid particles, except

pure water, ranging in size from approximately 0.005m to 100m in diameter

(Balaceanu and Stefan, 2004).

4. PM10:

Particulate matter is a ubiquitous pollutant, reflecting the fact that it has both natural and

anthropogenic sources. Natural sources of primary PM include windblown soil and

mineral particles, volcanic dust, sea salt spray, biological material such as pollen, spores

and bacteria and debris from forest fires (National Ambient Air Quality Objectives for

Particulate matter, 1998). PM10 refers to particulate matter that is 10 m or less in

diameter. PM10 is generally subdivided into a fine fraction of particles 2.5 m or less

(PM2.5), and a coarse fraction of particles larger than 2.5 m (National Ambient Air

Quality Objectives For Particulate matter, 1998). In the atmosphere the particulate

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matters (PMs) may be classed as either primary or secondary.

Primary particles are those such as carbon particles from combustion, mineral particles

derived from stone abrasion, and sea salt.

Secondary particles are those that are formed in the atmosphere by the chemical reaction

of the gases, which combine to form less volatile compounds that then condense into

particles (Balaceanu and Stefan, 2004).

Effects of Air Pollution:

Air pollution is a basic problem in today’s world. Exposure to ambient air pollution has

been linked to a number of different health outcomes, starting from modest transient

changes in the respiratory tract and impaired pulmonary function, continuing to restricted

activity/reduced performance, emergency room visits and hospital admiss ions and to

mortality. There is also increasing evidence for adverse effects of air pollution not only

on the respiratory system, but also on the cardiovascular system (WHO, 2004).

Physical damage functions relating health (mortality and morbidity) to air pollution levels

have been estimated over a number of years in different countries. Although the net effect

of pollutants on health is unclear, the Committee of the Medical Effects of Air Pollution

(COMEAP), set up by the UK government has found the strongest link between health

and pollution to be for particulates (PM10), sulphur dioxide (SO2) and ozone (O3) (Powe

Neil and Willisc Kenneth, 2002).

Sulphur dioxide:

Elevated concentrations of SO2 can be indicated by an odor of ‘burning matches’ and are

associated with human health impacts, including respiratory (breathing) effects,

especially asthma. Environmental effects include acid deposition and formation of PM2.5.

Vegetation, especially lichens, can be very sensitive to SO2 at relatively low

concentrations (Air Quality Monitoring Network, 2008). The gas irritates airways and

eyes and is known to cause longer-term heart diseases, other cardiovascular ailments, and

bronchitis. It also readily causes shortness of breath and coughing amongst asthma

sufferers. SO2 is also a major contributor to acid rain, which damages the environment

and upsets ecosystems (Chan and Li ,2007).

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Nitrogen oxides (NOx):

It causes severe respiratory problems, especially in children. When combined with water,

it forms nitric acid and other toxic nitrates. NO2 is also a main component in the

formation of ozone at the surface level. The gas irritates the lungs and has been known to

lower the immune system (Chan and Li ,2007). It may cause acidification and

eutrophication harmful to health (mainly the respiratory system), Materials, cultural

artifacts, vegetation and crops. Elevated concentrations of NO2 can also affect visibility

though creation of a ‘reddish brown’ haze. However, the effects of NO on vegetation is

coming under increasing investigation in Europe, while NOx is also a concern due to the

role it plays as a precursor pollutant for PM2.5 formation and its association with acid

deposition (Air Quality Monitoring Network, 2008).

Total suspended particulate (TSP):

TSP is associated with aesthetic and environmental impacts such as soiling of materials or

smothering of vegetation (Air Quality Monitoring Network, 2008). It may pose the

greatest threat to human health because, for the same mass, they absorb more toxic and

carcinogenic compounds than larger particles and penetrate more easily deep into the

lungs (Alias et al, 2007).

PM10:

The increases in particulate matter have been shown to cause small, reversible decrements

in lung function in normal asymptomatic children, and in both adults and children who

have some form of pre-existing respiratory condition, particularly asthma. These changes

were often accompanied, especially in adults, by increases in symptoms such as chronic

bronchitis or cough (National Ambient Air Quality Objectives For Particulate matter,

1998).

Monitoring Sites:

The main concern of the project is to measure the concentration of sulphur dioxide, NOX,

TSP and PM10 taking readings at different stations with the help of respirable dust

sampler.

The monitoring stations chosen should be free from any interference from the

surrounding living stock. Sampling is usually done at 1.5 m height. It was ensured that

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filter is parallel to the ground. To obtain a representative sample the sample should not be

placed under a tree, near a wall or other obstructions that would prevent free airflow from

the ambient atmosphere.

During inclement weather (including high winds), the entire sample is moved to a

protected location for servicing when practical. Before the new filter is installed, loose

particles from the inside surfaces of the sampler were removed and the surfaces around

the filter holder by wiping with a clean cloth. The clean installed filter was protected

when returning the sampler to the shelter.

In our case sampling was done generally at the rooftops of the respective sites so it was

well above the prescribed height that is 1.5 m and was free from any obstructions to flow

of air. (Suna and Singhdeo, 2008)

High-Volume Sampler (Model; APM 460): The high-volume (Hi-Vol) sampler is the

workhorse of air sampling and monitoring. The sampler uses a continuous duty blower to

suck in an air stream. When fitted with a particle size classifier, it separates particles

greater than 10μm size from the air stream. The air stream is then passed through a filter

paper to collect particles lesser than 10μm size (PM10). Gravimetric measurements yield

values of suspended particulate matter (SPM), as the sum of the two fractions, and PM10,

the material retained on the filter paper.

The filter paper can be used to determine benzene-soluble organics, metals, such as Pb,

Cd, etc., fluorides, radioactive materials and biologically active non- metals, sulphate,

nitrate and ammonium. ( Suna and Singhdeo, 2008).

The Hi-Vol APM 460 NL can be used to sample gases with the help of APM 411Gaseous

sampling attachment.

It consists of a set of 4 impingers (bubblers), carried in an ice tray. The impugners can be

operated either in series or parallel according to the requirement. The impingers can be

filled with up to 30 ml of the reacting reagent.

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Gaseous sampling requires only 0.2 to 2 L/min of airflow through individual impingers.

The impingers have a common outlet for the air after it passes through the reacting

reagent.

In this study we used 'Envirotech Respirable Dust Sampler (RDS), Model APM 460 NL'.

The sampler design is based on the know how developed at National Environmental

Engineering Research Institute (NEERI), Council of Scientific and Industrial Research

(CSIR), Govt. of India. The sampler is widely used in India in the National Air Quality

Monitoring Programme (NAMP) of the country.

Range and sensitivity:

Sampling at an average of 1.1m3/min for 24 hours, given an adequate sample, even in an

atmosphere having concentrations of particulates as low as 1μg/ m3. If particulates levels

are unusually high, a satisfactory sample may be obtained in 6 to 8 hours or less. For

determination of average concentrations of suspended particulates in ambient air, a

standard sampling period of 24 hours is recommended.

Weights are determined to the nearest milligram, air flow rate are determined to the

nearest 0.05 m3/min, times are determined to the nearest 1 minute, and mass

concentrations are reported to the nearest microgram per cubic meter (μg/ m3).

Interferences

Particulate matter that is oily, such as photochemical smog or wood smoke, may block the

filter and cause a rapid drop in airflow at a non uniform rate. Dense fog or high humidity

can cause the filter to become too wet and severely reduce the airflow through the filter.

Glass-fiber filters are comparatively insensitive to changes in relative humidity, but

collected particulates can be hygroscopic (Suna and Singhdeo, 2008).

Objective of the present study :

In view of the overwhelming evidence that air quality directly influences the health status

of individuals, in this study we wanted to moniter the air quality in Mysore in two

locations, namely in a down town area and ina residential area. Our in vitro experiments

have suggested that the respired air can affect risk factors for cardio vascular diseases.

Hence in this chapter the air quality of Mysore city is monitored for one year (2009).

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Materials and methods

Materials:

Mercuric chloride, Potassium chloride, Sodium chloride, EDTA di sodium salt,

Sulphamic Acid, pararosaniline, iodine, mercuric iodide, sodium thiosulfate pentahydrate,

sodium metabisulphite (Na2S2O5) , sodium sulphite (Na2SO3) , potassium iodide ,

Potassium iodate , sodium carbonate , Sodium hydroxide, Sodium Arsenite,

Sulphanilamide, (NEDA) and Sodium nitrite were from SRL INDIA. Formaldehyde,

HCl, phosphoric acid, hydrogen peroxide were from RANKEM INDIA.

Location for sample collection :

Down town area: The KSRTC building (Fig. 1A).

Fig 1A: GOOGLE map of KSRTC building in the down town area

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Residential area KSPCB building (Fig. 1B).

Fig 1B: GOOGLE map of KSPCB Building in a residential area

Methods:

The high-volume (Hi-Vol) APM 460 NL sampler was used for air sampling and

monitoring. Sulphur Dioxide, Nitrogen oxides, PM10 and TSP Present in the Ambient

Air was determined at two locations in Mysore city. One was at a downtown area and the

other at a residential area, according to the central pollution control board (CPCB)/Bureau

of Indian standard (BIS).

According to the CPCB (Central pollution control board) the methods prescribed for the

pollutant gases and the particulate pollutants are very sensitive ones yet percentages of

errors are very less. The methods prescribed for the gases SO2, NOx and the particulate

pollutants (TSP, PM10) are respectively:

1. Modified West and Gaeke method

2. Modified Jacob Hochheiser method

3. High Volume method

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Method for determination of Sulphur Dioxide in Air:

(Modified West and Gaeke Method)

Purpose:

Monitoring and analysis of sulphur dioxide in ambient air.

Standard

The national ambient air quality standards for sulphur dioxide is presented in the (table

1).

Table 1: Ambient air quality standards for sulphur dioxide

Pollutant Time

Weighted Average

Concentration in Ambient Air

Industrial, Residential, Rural and other Areas

Ecologically Sensitive Area (Notified by

Central Government)

Sulphur Dioxide (SO2), μg/m3

Annual *

24 Hours **

50

80

20

80

Annual Arithmetic mean of minimum 104 measurements in a year, at a particular site,

taken twice a week 24 hourly at uniform intervals.

** 24 hourly or 8 hourly or 1 hourly monitored values, as applicable, shall be

complied with 98% of the time in a year. 2% of the time, they may exceed the limits

but not on two consecutive days of monitoring.

Source: (CPCB, 2011)

Principle of the method

Modified West & Gaeke Method (IS 5182 Part 2 Method of Measurement of Air

Pollution: Sulphur dioxide). Sulphur dioxide from air is absorbed in a solution of

potassium tetrachloromercurate (TCM). A dichlorosulphitomercurate complex, which

resists oxidation by the oxygen in the air, is formed. Once formed, this complex is stable

to strong oxidants such as ozone and oxides of nitrogen and therefore, the absorber

solution may be stored for some time prior to analysis. The complex is made to react with

para-rosaniline and formaldehyde to form the intensely coloured pararosaniline

methylsulphonic acid. The absorbance of the solution is measured by means of a suitable

spectrophotometer.

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Reagents:

All the chemicals should meet specifications of Analytical Reagent grade.

Distilled water

Mercuric chloride

Potassium chloride / Sodium chloride

EDTA di sodium salt

Absorbing Reagent,

0.04 M Potassium Tetrachloro mercurate (TCM), Dissolve 10.86 g, mercuric chloride,

0.066 g EDTA, and 6.0 g potassium chloride or 4.68 gm sodium chloride in water and

bring to the mark in a 1 litre volumetric flask. Caution: highly poisonous if spilled on

skin, flush off with water immediately. The pH of this reagent should be approximately

4.0 but it has been shown that there is no appreciable difference in collection efficiency

over the range of pH 5 to pH 3. The absorbing reagent is normally stable for six months.

If, a precipitate forms, discard the reagent after recovering the mercury.

Sulphamic Acid (0.6%): Dissolve 0.6 g sulphamic acid in 100 ml distilled water.

Prepare fresh daily.

Formaldehyde (0.2%): Dilute 5 ml formaldehyde solution (36-38%) to 1 litre with

distilled water. Prepare fresh daily.

Purified Pararosaniline Stock Solution (0.2% Nominal): Dissolve 0.500 gm of

specially purified pararosaniline (PRA) in 100 ml of distilled water and keep for 2 days

(48 hours).

Pararosaniline Working Solution: 10 ml of stock PRA is taken in a 250 ml volumetric

flask. Add 15 ml conc. HCL and make up to volume with distilled water.

Stock Iodine Solution (0.1 N): Place 12.7 g iodine in a 250 ml beaker, add 40 g

potassium iodide and 25 ml water. Stir until all is dissolved, then dilute to 1 litre with

distilled water.

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Iodine Solution (0.01 N): Prepare approximately 0.01 N iodine solution by diluting 50

ml of stock solution to 500 ml with distilled water.

Starch Indicator Solution: Triturate 0.4 gm soluble starch and 0.002 g mercuric iodide

preservative with a little water and add the paste slowly to 200 ml boiling water. Continue

boiling until the solution is clear, cool, and transfer to a glass-stoppered bottle.

Potassium iodate.

Stock Sodium Thiosulfate Solution (0.1 N): Prepare a stock solution by placing 25 g

sodium thiosulfate pentahydrate in a beaker, add 0.1 g sodium carbonate and dissolve

using boiled, cooled distilled water making the solution up to a final volume of 1 litre.

Allow the solution to stand one day before standardizing.

To standardize, accurately weigh to the nearest 0.1 mg, 1.5 g primary standard potassium

iodate dried at 180oC, dissolve, and dilute to volume in a 500 ml volumetric flask. Into a

500 ml Iodine flask, transfer 50 ml of iodate solution by pipette. Add 2 g potassium

iodide and 10 ml of 0.1N hydrochloric acid and stopper the flask. After 5 min, titrate with

stock thiosulfate solution to a pale yellow. Add 5 ml starch indicator solution and

continue the titration until the blue colour disappears. Calculate the normality of the stock

solution.

Sodium Thiosulphate Titrant (0.01 N): Dilute 100 ml of the stock thiosulfate solution to

1 litre with freshly boiled and cooled distilled water.

Standardized Sulphite Solution for Preparation of Working Sulphite - TCM Solution

Dissolve 0.30 g sodium metabisulphite (Na2S2O5) or 0.40 g sodium sulphite (Na2SO3) in

500 ml of recently boiled, cooled, distilled water. Sulphite solution is unstable; it is,

therefore, important to use water of the highest purity to minimize this instability. This

solution contains the equivalent of 320-400 μg/ml of SO2.

Working Sulphite-TCM Solution - Measure 2 ml of the standard solution into a 100 ml

volumetric flask by pipette and bring to mark with 0.04 M TCM. Calculate the

concentration of sulphur dioxide in the working solution in micrograms of sulphur

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dioxide per millilitre. This solution is stable for 30 days if kept in the refrigerator at 5oC.

If not kept at 5oC, prepare fresh daily.

Sampling

Place 30 ml of absorbing solution in an impinger and sample for four hours at the flow

rate of 1 L/min. After sampling measure the volume of sample and transfer to a sample

storage bottle.

Analysis

Replace any water lost by evaporation during sampling by adding distilled water up to the

calibration mark on the absorber. Mix thoroughly, pipette out 10/20 ml of the collected

sample into a 25 ml volumetric flask. Add 1 ml 0.6% sulphamic acid and allow reacting

for 10 minutes to destroy the nitrite resulting from oxides of nitrogen. Add 2 ml of 0.2%

formaldehyde solution and 2 ml pararosaniline solution and make up to 25 ml with

distilled water. Prepare a blank in the same manner using 10 ml of unexposed absorbing

reagent. After a 30 min colour development interval and before 60 minutes, measure and

record the absorbance of samples and reagent blank at 560 nm. Use distilled water; not

the reagent blank, as the optical reference

Calibration

The actual concentration of the sulphite solution is determined by adding excess iodine

and back titrating with standard sodium thiosulfate solution. To back-titrate, measure, by

pipette, 50 ml of the 0.01 N iodine solution into each of two 500 ml iodine flasks A and

B. To flask A (blank) add 25 ml distilled water and into flask B (sample) measure 25 ml

sulphite solution by pipette. Stopper the flasks and allow to react for 5 minutes. Prepare

the working sulphite-TCM solution at the same time iodine solution is added to the flasks.

By means of a burette containing standardized 0.01 N thiosulfate, titrate each flask in turn

to a pale yellow. Then add 5 ml starch solution and continue the titration until the blue

colour disappears.

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Preparation of Standards

Measure 0.5 ml, 1.0 ml, 1.5 ml, 2.0 ml, 2.5 ml, 3.0 ml, 3.5 ml and 4.0 ml of working

sulphite TCM solution in 25 ml volumetric flask. Add sufficient TCM solution to each

flask to bring the volume to approximately 10 ml. Then add the remaining reagents as

described in the procedure for analysis. A reagent blank with 10 ml absorbing solution is

also prepared. Read the absorbance of each standard and reagent blank.

Standard Curve

Plot a curve absorbance (Y axis) versus concentration (X axis). Draw a line of best fit and

determine the slope. The reciprocal of slope gives the calibration factor (CF).

Calculation

Concentration of sulphite solution:

(V1-V2) x N x K C = ____________ V Where,

C = SO2 concentration in μ/ml

V1 = Volume of thiosulfate for blank, ml

V2 = Volume of thiosulfate for sample, ml

N = Normality of thiosulfate

K = 32000 (Milliequivalent weight SO2/μg)

V = Volume of standard sulphite solution, ml

C (SO2 μg/m3)=(As –Ab) x CF x Vs / Va xVt

C (SO2) = Concentration of Sulphur dioxide, μg/m3

As = Absorbance of sample

Ab = Absorbance of reagent blank

CF = Calibration factor

Va = Volume of air sampled, m3

Vs =Volume of sample, ml

Vt =Volume of aliquot taken for analysis, ml

(CPCB, 2011)

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Method for determination of Nitrogen dioxide in ambient air

(Modified Jacob and Hochheiser Method)

Purpose

Monitoring of nitrogen dioxide in ambient.

Standard

The national ambient air quality standard for nitrogen dioxide is presented in the (table 2).

Table 2: Ambient air quality standard for nitrogen dioxide

Pollutant Time

Weighted

Average

Concentration in Ambient Air

Industrial, Residential,

Rural and other Areas

Ecologically Sensitive Area (Notified by

Central Government)

Nitrogen dioxide (NO2), μg/m3

Annual *

24 Hours **

40

80

30

80

Annual Arithmetic mean of minimum 104 measurements in a year, at a particular site,

taken twice a week 24 hourly at uniform intervals.

** 24 hourly or 8 hourly or 1 hourly monitored values, as applicable, shall be

complied with 98% of the time in a year. 2% of the time, they may exceed the limits

but not on two consecutive days of monitoring.

SOURCE: (CPCB, 2011)

Principle of the method

Modified Jacobs & Hochheiser Method (IS 5182 Part 6 Methods for Measurement of Air

Pollution: Oxides of nitrogen). Ambient nitrogen dioxide (NO2) is collected by bubbling

air through a solution of sodium hydroxide and sodium arsenite. The concentration of

nitrite ion (NO2) produced during sampling is determined colorimetrically by reacting the

nitrite ion with phosphoric acid, sulfanilamide, and N-(1-naphthyl)- ethylenediamine di-

hydrochloride (NEDA) and measuring the absorbance of the highly coloured azo-dye at

540 n m.

Reagents:

Distilled water

Sodium hydroxide

Sodium Arsenite

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Absorbing solution: (Dissolve 4.0 g of sodium hydroxide in distilled water, add 1.0 g of

sodium Arsenite, and dilute to 1,000 ml with distilled water)

Sulphanilamide - Melting point 165 to 167oC

N-(1-Naphthyl)-ethylenediamine Di-hydrochloride (NEDA) - A 1% aqueous solution

should have only one absorption peak at 320 nm over the range of 260-400 nm. NEDA

showing more than one absorption peak over this range is impure and should not be used.

Hydrogen Peroxide - 30%

Phosphoric Acid - 85%

Sulphanilamide Solution - Dissolve 20 g of sulphanilamide in 700 ml of distilled water.

Add, with mixing, 50 ml of 85% phosphoric acid and dilute to 1,000 ml. This solution is

stable for one month, if refrigerated

NEDA Solution - Dissolve 0.5 g of NEDA in 500 ml of distilled water. This solution is

stable for one month, if refrigerated and protected from light

Hydrogen Peroxide Solution - Dilute 0.2 ml of 30% hydrogen peroxide to 250 ml with

distilled water. This solution may be used for one month, if, refrigerated and protected

from light.

Sodium nitrite - Assay of 97% NaNO2 or greater

Sodium nitrite stock solution (1000 μg NO2/ml) Dissolve desiccated NaNO2 1.5g (assay

100%) or 1.5/assay% (for assay less than 100%) in 1000 ml of distilled water.

Sodium nitrite solution (10 μg NO2/ml.)

Sodium nitrite working solution (1 μg NO2/ml) (Dilute with absorbing reagent, prepare

fresh daily)

Sampling

Place 30 ml of absorbing solution in an impinger and sample for four hour at the flow rate

of 0.2 to 1 L/min. After sampling measure the volume of sample and transfer to a sample

storage bottle.

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Analysis

Replace any water lost by evaporation during sampling by adding distilled water up to the

calibration mark on the absorber, mix thoroughly. Pipette out 10 ml of the collected

sample into a 50 ml volumetric flask. Pipette in 1 ml of hydrogen peroxide solution, 10

ml of sulphanilamide solution, and 1.4 ml of NEDA solution, with thorough mixing after

the addition of each reagent and make up to 50 ml with distilled water.

Prepare a blank in the same manner using 10 ml of unexposed absorbing reagent. After a

10 min colour development interval, measure and record the absorbance of samples and

reagent blank at 540 nm.

Use distilled water; not the reagent blank, as the optical reference Samples with an

absorbance greater than 1.0 must be re-analyzed after diluting an aliquot of the collected

samples with an equal quantity of unexposed absorbing reagent. A randomly selected 5-

10% of the samples should be re-analyzed as apart of an internal quality assurance

program.

Calibration

Preparation of Standards

Pipette 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15 and 20 ml of working standard solution in to 50

ml volumetric flask. Fill to 20 ml mark with absorbing solution. A reagent blank with 10

ml absorbing solution is also prepared. Add reagents to each volumetr ic flask as in the

procedure for analysis. Read the absorbance of each standard and reagent blank against

distilled water reference.

8.2. Standard Curve:

Plot a curve absorbance (Y axis) versus concentration (X axis). Draw a line of best fit and

determine the slope. The reciprocal of slope gives the calibration factor (CF).

Calculation

C (NO2 μg/m3)=(As –Ab)x CF x Vs / Va x Vt x0.82

Where, C NO2 = Concentration of Nitrogen dioxide, μg/m3

As = Absorbance of sample

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Ab = Absorbance of reagent blank

CF = Calibration factor

Va = Volume of air sampled, m3

Vs = Volume of sample, ml

Vt = Volume of aliquot taken for analysis, ml

0.82 = Sampling efficiency

(CPCB, 2011)

Determination of RSPM AND SPM:

Standard

The national ambient air quality standards for Particulate Matter PM10 is presented in the

(table 3).

Table 3: Ambient air quality standards for Particulate Matter PM 10.

Pollutant Time

Weighted Average

Concentration in Ambient Air

Industrial, Residential, Rural and other Areas

Ecologically Sensitive Area (Notified by

Central Government)

Particulate Matter, PM10, μg/m3

Annual * 24 Hours **

60 100

60 100

Annual Arithmetic mean of minimum 104 measurements in a year, at a particular site,

taken twice a week 24 hourly at uniform intervals.

** 24 hourly or 8 hourly or 1 hourly monitored values, as applicable, shall be

complied with 98% of the time in a year. 2% of the time, they may exceed the limits

but not on two consecutive days of monitoring.

SOURCE: (CPCB, 2011)

Apparatus

Sampler: (Envirotech Respirable Dust Sampler (RDS), Model APM 460 NL)

Filter : A Glass fibre filter of 20.3 X 25.4 cm (8 X 10 in) size .

It is a compact unit consisting a protective housing, blower, voltage stabilizer, automatic

time and time totalizer, rotameter, gaseous sampling assembly, filter holder capable of

supporting a 20.3 x 25.4 cm. glass fiber filter.

Air is drawn into a covered housing and through a filter by a high flow rate blower at 1.1

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to 1.5 3/min that allows suspended particulate matter with diameters <10μm (Stokes

equivalent diameter) to collect on the filtmer surface. Particles with diameters of 0.1 to 10

μm are collected on glass fiber filters.

The mass concentration of PM10 μg/ 3 in ambient air is computed by measuring the mass

of PM10 collected and the volume of air sampled. The size of the sample collected is

usually adequate for further analysis of trace elements. The sample of air is first drawn

into a cyclone separator, which passes only the smaller particles with diameter less than

10 μm. These are then collected on the filter, as before, while the larger “non-respirable”

particulates are collected in a removable dust collector cup.

PM10 is calculated by measuring the mass collected on the filter and the volume of air

sampled, while NRPM is calculated by measuring the mass collected on the dust collector

cup and the volume of air sampled.

Calculation

RSPM respirable suspended particulate matter.(PM10) is calculated by measuring the

mass collected on the filter and the volume of air sampled.

C PM10 (RSPM) μg/m3 =(Wf –Wi) x 106 /V

Where:

RSPM = Mass concentration of respirable suspended particles in mg/m3

Wi = Initial weight of filter in g

Wf = Final weight of filter in g

V = Volume of air sampled in m3

106 = Conversion of g to g.

Calculation of Volume of Air Sampled

V=QT

Q = Average flow rate in m3/minute

V = Volume of air sampled in m3

T = Total sampling time in minute

(CPCB, 2011)

SPM Suspended particulate matter is calculated by sum of RSPM and NRPM

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Results:

The level of air pollution in Mysore city during the year 2009 (January to December) was

collected and shown here. The collection of samples were made at two places, one was in

the downtown area (KSRTC Building) and the other was at a residential area (KSPCB

building) (See Fig 1A and B).

The variation of the pollutants, namely, SO2, NO2, RSPM and SPM during the entire year

is shown in Fig 2A and B. Fig 2A gives the data for the down town area and Fig 2B gives

the data for the Residential area.

Fig 2A: Air Pollution in downtown area, for the year 2009

Air pollution monitored at KSRTC Building. Samples were collected on 10 days in a month. The mean for a month was plotted against concentration of the air pollutant. SO2: sulfur dioxide, NO2 : Nitric oxide, SPM : suspended particulate matter, RSPM :

Respirable suspended particulate matter.

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Fig 2B: Air Pollution in a residential area, for the year 2009

Air pollution monitored at KSPCB Building. Samples were collected on 10 days in a

month. The mean for a month was plotted against concentration of the air pollutant. SO2:

sulfur dioxide, NO2: Nitric oxide, SPM: suspended particulate matter, RSPM : Respirable

suspended particulate matter.

The variation of pollution for the month of January is shown in Fig 3A and 3B.

Fig 3A: Air Pollution in downtown area, for January 2009

Air pollution monitored at KSRTC Building on specified days. The mean for a day was

plotted against concentration of the air pollutant. SO2: sulfhur dioxide, NO2: Nitric oxide,

SPM : suspended particulate matter, RSPM : Respirable suspended particulate matter.

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Fig 3B: Air Pollution in a residential area, for January 2009

Air pollution monitored at KSPCB Building on specified days. The mean for a day was

plotted against concentration of the air pollutant. SO2 : sulfhur dioxide, NO2 : Nitric oxide, SPM : suspended particulate matter, RSPM : Respirable suspended particulate

matter.

The variation of the concentration of pollutants in one day is shown in Fig 4 A through D.

Fig 4A: Variation in the SO2 levels in one day at down town area (KSRTC) and

Residential area (KSPCB).

SO2 levels were monitered every 4 hrs at a down town area(KSRTC Building) and a

residential area (KSPCB building) The results are Mean + Sd (n=10)

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Fig 4B: Variation in the NO2 levels in one day at down town area (KSRTC) and

Residential area (KSPCB).

NO2 levels were monitered every 4 hrs at a down town area(KSRTC Building) and a

residential area (KSPCB building) The results are Mean + Sd (n=10)

Fig 4C: Variation in the RSPM levels in one day at Down town area (KSRTC) and

Residential area(KSPCB)

RSPM levels were monitered every 4 hrs at a down town area(KSRTC Building) and a residential area (KSPCB building) The results are Mean + Sd (n=10)

110

Fig 4D: Variation in the SPM levels in one day at Down town area (KSRTC) and

Residential area(KSPCB)

levels were monitered every 4 hrs at a down town area(KSRTC Building) and a

residential area (KSPCB building) The results are Mean + Sd (n=10)

The maximum pollutant concentration was observed during the mid day both in the down

town area and in the residential area. levels were monitered every 4 hrs at a down town

area(KSRTC Building) and a residential area (KSPCB building) The results are Mean +

Sd (n=10)

The annual average pollutant level for Mysore city for the year 2009 is given in Table 4.

Table 4: Annual Average Pollutant levels in Mysore

Pollutant Permissible

Level ( µg/ m3)

Down town area

(µg/ m3 )

Residential area

(µg/ m3)

SO2 50 14.7 13.6

NO2 40 31.3 28.1

RSPM 60 54.4 41.3

SPM 60 108.3 79.4

The average pollutant level was calculated for all the observations made during the year.

The SPM in both the down town area and the residential area exceeded the permissible level. The level of pollutants in the down town area was more than that in the residential area.

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Discussion:

Epidemiological, clinical, and experimental evidence correlates the levels of ambient air

pollution with adverse respiratory and cardiovascular effects. Road traffic is a major

factor in ambient air pollution which contributes to pollutants like fine particulate matter,

carbon monoxide and oxides of nitrogen. Traffic emissions result in small scale spatial

variations and higher concentrations within short distances from major roads. Air

pollution data from fixed monitoring stations may be inadequate to study traffic related

air pollution and health outcomes, especially for those living near busy roads. The two

monitoring stations used in this study, namely the KSRTC building and KSPCB building

are in close proximity to busy roads. The monitoring centre is within 300 mts of the main

road.

The health consequences are unlikely to be the consequence of one or a few single

pollutants but, more likely, are the result of the complex mixture of primary and

secondary interacting constituents that lead to the observed effects through common (eg

oxidant stress) and/or distinct (direct toxicity) pathways. Experimental studies are unable

to mimic fully the ambient mixture, whereas epidemiological studies have limited

capabilities to disentangle effects of specific constituents or sources of pollutants. An

expanding body of epidemiological research suggests that traffic related exposure is

associated with acute and chronic respiratory effects. For example, residential proximity

to busy roads is associated with a variety of adverse respiratory health outcomes

including asthma. However, the effect of traffic air pollution on adult lung function

remains inconclusive; exposure to automobile exhaust was associated with lower lung

function in adults in some studies, but not others (Künzlia andTagerb, 2005). Other

studies have identified consistent association between cardiopulmonary mortality and

living near a major road, but not with estimated ambient background concentration of the

traffic (Hoek et al.2002). NO2 on the other hand may amplify effects of other pollutants

or allergens (Kraft et. al.,2005). The characterisation of exposure to traffic emissions has

been improved considerably in recent studies; and it becomes increasingly apparent that

living within 0–100 meters to the emissions from busy roads may impose a health threat

(Schlisenger et al. 2005).

The pollution levels reported for Mysore city by the pollution control Board are Low in

Industrial area as well as residential areas. However from our study except for particulate

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matter, the other pollutants were low. The residential areas had lower levels of the

pollutants than the down town area.

Interestingly there was a spurt in the pollution level in the month of October and in the

month of January. It is possible that the festive seasons during these months and the

associated fire cracker burning could have added to the particulate matter as well as SO2.

The interesting question is whether reductions of ambient pollution concentrations would

reduce the risk of lund diseases and cardio vascular diseases. An increasing body of

“intervention-type” studies confirms that improvements in air quality, in fact, do lead to

health benefits in the population. The 1991 coal ban in Dublin was followed by an

immediate decline in pollution and a sustained ~10% decrease in cardiovascular

mortality, corresponding to ~240–250 fewer cardiovascular deaths per year (Clancy et.al.,

2002). Even subtle improvements in air quality as observed in Switzerland over the past

10 years led to reductions in respiratory symptoms among children (Bayer-Oglesby

et.al.,2005), and preliminary findings of the SAPALDIA study suggest these air quality

changes correlate with reduced age-related lung function decline rates in adults

(Ackermann-Liebrich, 2005). Lung growth of children moving into cleaner areas during

the Children’s Health Study follow-up also improved whereas those moving into more

polluted communities experienced reduced growth rates (Avol et.al.,2001). An

experiment has shown that a non-specific intervention such as a particle filter on a diesel

engine, combined with the use of low sulphur diesel fuel can reduce drastically, if not

eliminate, a myriad of pollutants and toxic reactions observed in the lungs of mice after

exposure to diesel exhaust (McDonald et.al.2004).

Last but not least, pollution needs to be reduced, and air quality and health need to be

monitored to be aware of trends and consequences. Stringent clean air quality policies are

required on both the national and international level to curb air pollution as a primary

preventive strategy.

113

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