JavaScript must be enabled in order for you to use the Site in standard view. However, it seems JavaScript is either disabled or not supported by your browser. To use standard view, enable JavaScript by changing your browser options.

| Last Updated:: 21/11/2017

Air Pollution

Air Pollution
Air Pollution in Tamil Nadu  
 
1. Introduction
Air pollution is defined as the introduction of particulates, biological molecules, or other harmful materials into the Earth's atmosphere, possibly that cause disease, death to humans, damage to food crops, or the natural or built environment. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems. Indoor air pollution and urban air quality are listed as two of the world’s worst toxic pollution problems.    
 
One of the formal definitions of air pollution is as follows:-
"The presence in the atmosphere in the atmosphere of one or more contaminants in such quality and for such duration as is injurious, or tends to be injurious, to human health or welfare, animal or plant life".  It is the contamination of air by the discharge of harmful substances.  Air pollution can cause health problems and it can also damage the environment and property.  It has caused thinning of the protective ozone layer of the atmosphere, which is leading to climate. 
 
2.  Causes of pollution         
There are various activities or factors which are responsible for releasing pollutants into the atmosphere.  These sources can be classified into two major categories.   
 
2.1. Anthropogenic (man-made) sources:
These are mostly due to the burning of multiple types of fuel. Anthropogenic sources include the following:
                 Stationary sources include stacks of power plants, manufacturing factories, waste incinerators, furnaces and other types of fuel-burning devices. In less developed countries traditional biomass burning is the major source of air pollutants; Traditional biomass includes wood, crop waste and cow-dung. 
Mobile Sources include vehicles, marine vessels, and aircrafts. Fumes from paint, hair spray, varnish, aerosol sprays and other solvents also contribute towards air pollution. Waste deposition in landfills; generate methane during the breakdown of compounds. Methane being highly flammable and forms explosive mixtures with air. Methane is also an asphyxiant and displaces oxygen in an enclosed space. 
Military resources, such as nuclear weapons and toxic gases are also key sources of air pollution. 
 
2.2. Natural sources:
Dust from natural sources, mostly large areas of land with few or no vegetation. Radon gas from radioactive decay within the Earth's crust. Radon is a naturally occurring, radioactive noble gas that is formed from the decay of radium. It is considered to be a health hazard. Radon gas from natural sources can accumulate in buildings, especially in confined areas is the one of the most frequent cause of lung cancer. Smoke and carbon monoxide from wildfires Volcanic activity, produces sulfur, chlorine, and ash particulates. A pollutant can be of natural origin or man-made. Pollutants are classified as primary or secondary.  
            Primary pollutants are usually produced from a process, such as ash from a volcanic eruption. Other examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories. 
            Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant. Some pollutants may be both primary and secondary: they are both emitted directly and formed from other primary pollutants.  In India the Major source of air pollution include Fuel wood and biomass burning in rural and urban India, Most of India uses Fuel wood and biomass cakes for cooking and general heating needs. Cook stoves using biomass are present in over 100 million Indian households, and are used two to three times a day. Majority of Indians still use traditional fuels such as dried cow dung, agricultural wastes, and firewood as cooking fuel. 
 
3. Major primary pollutants produced by human activity include
                a) Sulphur oxides (SOx) - particularly sulfur dioxide, a chemical compound with the formula SO2 is produced by volcanoes and various industrial processes. Coal and petroleum often contain sulfur compounds, and their combustion releases sulfur dioxide. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and leads to the formation of acid rain. 
                b) Nitrogen oxides (NOx)-Nitrogen oxides, particularly nitrogen dioxide, are expelled from high temperature combustion, and are also produced during thunderstorms by electric discharge. It is a chemical compound with the formula NO2. It is one of  the most prominent air pollutants. 
          c) Carbon monoxide (CO)- CO is also a toxic gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide. 
                d) Volatile organic compounds - VOCs are a well-known outdoor air pollutantThey are categorized as either methane (CH4) or non-methane (NMVOCs).Methane is a greenhouse gas which has contributed to enhance global warming. The aromatic NMVOCs such as benzene, toluene and xylene are suspected carcinogens and may lead to leukemia with prolonged exposure. 
       e) Particulate Matter: Particulates, alternatively referred to as particulate matter (PM), atmospheric particulate matter, or fine particles, are particles of solid or liquid suspended in a gas.Aerosols In contrast, aerosol refers to combined particles and gas. They can occur naturally, from volcanoes, dust storms, forest fires, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and industrial processes also generate significant amounts of aerosols. 
              f) Chlorofluorocarbons (CFCs) - harmful to the ozone layer. These are gases which are released from airconditioners, refrigerators. CFC's on being released into the air rises to stratosphere and react with other gases and damage the ozone layer. This allows harmful ultraviolet rays to reach the earth's surface causing skin cancer and diseases to the eye. 
 
4. Secondary pollutants include:
Particulates created from gaseous primary pollutants are called secondary pollutants. Smog is a kind of secondary air pollution. Smog results from large amounts of coal burning in an area caused by a mixture of smoke and sulfur dioxide. Smog also comes from vehicular and industrial emissions that are acted on in the atmosphere by ultraviolet light from the sun to form secondary pollutants that also combine with the primary emissions to form photochemical smog. 
a) Ground level ozone (O3) is formed from NOx and VOCs. Ozone (O3) is a key constituent of the troposphere. It is also an important constituent of certain regions of the stratosphere commonly known as the Ozone layer. 
b) Peroxyacetyl nitrate (PAN) – is also formed from NOx and VOCs. 
 
5. Status of Tamil Nadu
Tamil Nadu Pollution Control Board is operating eight ambient air quality monitoring stations in Chennai under two monitoring programmes:   
 
 
Table 1. NATIONAL AIR QUALITY MONITORING PROGRAMME (NAMP)
 
   Status Of Air Quality Of Important Cities/Towns Of Tamilnadu – Under National Air Quality Monitoring Programme (Namp) Annual Average Concentrations Of Air Pollutants, 2015 – 2016 
 
 

 
S.
No.
 
City & Location
 
Category
 
Annual Average concentrations of Air Pollutants in µg/m3
 
SO₂
 
NO₂
 
RSPM
 
Max
 
Min
 
 Avg
 
 Max
 
 Min
 
 Avg
 
 Max
 
 Min
 
 Avg
  1
 CHENNAI
a)
Kathivakkam
Industrial
18
10
13
24
12
14
93
27
49
b)
Manali
Industrial
19
10
14
23
13
17
79
17
43
c)
Thirvottiyur
Industrial
17
10
13
22
12
17
73
25
44
d)
Anna Nagar
Residential
26
9
13
41
13
19
250
28
91
e)
Adyar
Residential
18
8
12
22
11
16
80
23
44
f)
Kilpauk
Commercial (Traffic-intersection)
32
9
15
32
13
20
147
29
79
g)
Thiyagarayanagar
Commercial (Traffic-intersection)
28
11
15
37
14
23
244
38
94
h)
Nungambakkam
Commercial (Traffic-intersection)
32
10
15
44
13
21
263
35
98
 2
 COIMBATORE
a)
DCO
Mixed
9
4
4
40
17
25
114
8
45
b)
Pooniyaraja
puram
Residential
4
4
4
32
16
23
123
16
47
C)
SIDCO
Industrial
8
4
4
52
20
27
122
16
52
  3
  THOOTHUKUDI
a)
Raja Agencies
Industrial
20
10
16
29
14
24
663
30
190
b)
AVM Buildings
Mixed
14
6
11
18
9
15
475
16
91
C)
SIPCOT
Industrial
19
8
16
29
11
23
383
28
118

4
  MADURAI
a)
M/S Susee Cars & Trucks (p) Ltd.,
Industrial
21
10
15
48
14
23
128
31
63
b)
Madurai Corporation Offices (SZ)
Mixed
23
9
16
48
18
27
119
36
79
C)
Highways project Buildings
Residential
15
8
10
36
12
21
113
22
53
  5
 SALEM
a)
Sowdeswari College Building
Mixed
14
6
8
35
22
27
122
41
53
 6
TRICHY
a)
Gandhi Market
Commercial
25
7
15
28
13
21
150
53
126
b)
Main Guard Gate
Traffic Inter Section
20
10
15
25
18
22
157
90
125

Source: TNPCB   
 
5.1 CHENNAI AMBIENT AIR QUALITY MONITORING (CAAQM) PROGRAMME
Under NAMP three ambient air quality monitoring stations are functioning on 24 hours basis, twice a week.  The samples collected from NAMP stations are analysed for the Total Suspended Particulate Matter (TSPM), Respirable Suspended Particulate Matter (RSPM).   (RSPM is particulate matter less than 10 microns) and gaseous pollutants such as Sulphur di oxide (SO2) and Oxides of Nitrogen (NOx).
Under CAAQM programme, TNPCB is operating five monitoring stations on 24 hours basis two stations per day on all working days. The pollutants measured in the CAAQM stations are Sulphur di oxide (SO2), Oxides of Nitrogen (NOx), Respirable Suspended Particulate Matter (RSPM) and Total suspended particulate matter (TSPM) in all stations. 
The eight ambient air quality monitoring stations in Chennai are:
 Table 2. Ambient Air Quality Monitoring Stations
I
Kathivakkam (NAMP)
Industrial area
II
Manali (NAMP)
Industrial area
III
Thiruvottiyur (NAMP)
Industrial area
IV
Kilpauk (CAAQM)
Commercial (traffic inter-section
V
Thiyagaraya Nagar (CAAQM)
Commercial (traffic inter – section)
VI
Vallalar Nagar (CAAQM)
Commercial (traffic inter – section)
VII
Anna Nagar (CAAQM)
Residential area
VIII
Adyar (CAAQM)
Residential area
 
  
 
 
 
 
                                                     Source: Tamil Nadu Pollution Control Board
 
The ambient air quality data collected from the above mentioned air quality monitoring stations (NAMP) indicate that all the parameters such as sulphur dioxide, oxides of nitrogen, total suspended particulate matter and respirable dust particulates are found to be well controlled in the industrial area die to the effective monitoring of  industrial source emissions by the TNPCB. 
 
In general, under CAAQM project the ambient air pollutants such as sulphur dioxide and oxides of nitrogen are well within the standards in Chennai city limit, where as total suspended particulate matter and respirable suspended particulate matter (PM) levels exceeded the permissible limit at all stations except Adyar mainly due to the dust contributed by pipe line, telephone/electrical cable laying activities on the road and also due to the resuspension of traffic dust generated from automobile emissions and heavy vehicular traffic and pedestrian movement. 
 
 
 
6.  Action Taken to Prevent Air Pollution in Tamil Nadu
 
(a)   Industrial Pollution 
 
 The salient features of actions taken to control industrial pollution are as follows:
·         No new polluting units are permitted within the city.
·         No new incinerators are permitted within the city, old incinerators being phased out.
·         Common facilities are set up outside the city for incineration of Bio-medical Waste.
·        The industries have been directed to develop a green belt of minimum 33% of the project area.
·         Green belt is also being developed by industries on road sides as avenue plantations.
·         Renewal of the consent is based on compliance with this condition
·        Periodic inspection of industrial units is to be fitted with online stack monitor connected to the pollution control board – CARE Air centre. 
 
(b)   Vehicular Pollution
The salient features of action taken to control vehicular pollution are as follows:
·         Bharat Stage –II norms have been implemented for the registration of new passenger car from 1-7-2011.
·         Emission norms for in-use vehicles in consultation with MoRTH & MoEF have been implemented in Chennai city for all vehicles from 1-1-1997.
·         Catalytic Converter fitted passenger car have been registered since, 1997.
 
·Further information please refer:

       I.        Tamil Nadu pollution control board