Air Pollution
Syllabus
• Air Pollution, Composition of Air, Structure
of atmosphere, Ambient air quality
standards, Classification of air pollutants,
Sources of common air pollutants like SPM,
SO2, NOX, Natural and anthropogenic
Sources, and its effects.
Important Questions
• Describe the Different Air Pollutants
• Explain the effects of air pollution on human beings and
animals.
• Describe the effects of air pollution on humans.
• Enumerate the different air pollutants and explain its effect on
human beings.
• Enlist common air pollutants stating their permissible limits as
per ambient air quality standards. Discuss the effects of high
carbon monoxide’s presence in atmosphere upon human
beings.
• What do you understand by primary and secondary air
Pollutant? Discuss the health hazards of air pollution?
Important Questions
• Describe Structure of Atmospheric Air . Give
types and effects of common air pollutants in
detail.
• Discuss various air pollutants.
• Discuss hazardous effects of air pollutants.
• Enlist natural and human sources of Air
Pollution. Explain any one briefly and list out
the common atmospheric pollutants.
• State Indian Ambient Air Quality Standards.
Air Pollution
• Definition:- Air pollution is define as
“ Excessive concentration of foreign matter in air, which
adversely affects the well being of individuals or causes damage
to the property”.
Composition of Air
Atmosphere and its Structure
• Atmosphere:- The gaseous layer surrounding the earth is
known as atmosphere.
• The atmosphere is the life supporting mantle, surrounding the
earth.
• The atmosphere surrounds the earth up to 700 km, atmosphere
is subdivided as
• Troposphere:- ( 0 To 12 Km) Contains 75 % of the gases in the
atmosphere. This is where we live and weather occurs.
• Stratosphere:- (12 – 50 Km) this layer contains ozone layer.
Ozone acts as a shield for the earth’s surface. It absorbs
ultraviolet radiations from the sun. This causes temperature
increase in the upper part of the layer.
• Mesosphere:- ( 50 to 80 Km) This is the coldest region of the
atmosphere. This layer protects the earth from meteoroid. They
burn up in this area.
• Thermosphere:- ( 80 Km and above) The air is very thin in this
region. Thermosphere means “Heat Sphere”. The temperature is
very high in this region
• This layer contains:• (a) Ionosphere:-This is the lower part of the thermosphere. It
extends from 80 Km – 550 Km. This layer generally helps in
radio communication.
• (b) Exosphere:- The upper part of the thermosphere. It extends
from 550 km and above. Air is very thin here this is the area
where satellite orbits the earth.
Structure of Atmosphere
* Ministry of Environment and Forests, Government of India notification,1994
** Particle size less than 10 µm
Ambient Air Quality Standards
Pollutant
Time Weighted
Average
Concentration in Ambient Air
Industrial Area
Residential, Rural
and other
Sensitive Area
Sulphur Dioxide
(SO2)
Annual
24 hours
80 µg/m3
120 µg/m3
60 µg/m3
80 µg/m3
15 µg/m3
30 µg/m3
Oxides of Nitrogen
(NO2)
Annual
24 hours
80 µg/m3
120 µg/m3
60 µg/m3
80 µg/m3
15 µg/m3
30 µg/m3
Suspended
Particulate Matter
(SPM)
Annual
24 hours
360 µg/m3
500 µg/m3
140 µg/m3
200 µg/m3
70 µg/m3
100 µg/m3
120 µg/m3
150 µg/m3
60 µg/m3
100 µg/m3
50 µg/m3
75 µg/m3
Respirable **
Annual
Particulate Matter
24 hours
(RPM)
Lead (pb)
Annual
24 hours
1.0 µg/m3
1.5 µg/m3
0.75 µg/m3
1.00 µg/m3
0.50 µg/m3
0.75 µg/m3
Carbon
Monoxide(CO)
8 hours
1 hour
5.0 µg/m3
10.0 µg/m3
2.0 µg/m3
4.0 µg/m3
1.0 µg/m3
2.0 µg/m3
Major Sources of Air Pollution
Major Sources of Air Pollution
• Natural Sources:- The natural sources of air pollution are
volcanic eruptions, releasing of poisonous gases like SO2 ( Sulfur
dioxide), Hydrogen sulphide (H2S), Carbon Monoxide(CO),
Forest fires, natural organic and inorganic decays, Pollen grains,
wind blown dust, among them pollen grain are important
because it causes allergic reactions in individuals.
Anthropogenic Sources
• Rapid Industrialization:- The Industries such as pulp and
paper, chemical, metallurgical plants, refineries are responsible
for air pollution, the most common pollutants are CO2, SO2, CO,
NO, H2S etc.
• Transportation:- Automobile exhausts release smoke. The
smoke is a result of incomplete combustion of carbonaceous
matter. The common pollutants are CO ( Carbon Monoxide), CO2,
and Hydrocarbons.
• Burning of Fossil fuels and fires:- The conventional sources of
energy are wood, coal, and fossil fuels. The byproducts of fossil
fuels is nothing but poisonous gases such as CO, CH4 (methane),
SO2, and NOX.
• Deforestation:- The balance of O2 and CO2 is maintained in the
nature by the vegetation. The deforestation by man for his own
needs has disturbed the balance of CO2 and O2, Concentration.
• Increase in Population:- an increase in population leads to
global warming and emission of green house gases. It also
contributes to losses in forest cover and loss of wild life.
• Agriculture activities:- Various pesticides and insecticides are
used for agricultural purposes. Thus they cause air pollution.
• Radioactive fallout:- Nuclear reaction, nuclear weapon testing
contributes towards Nuclear pollution. Nuclear Pollutants are
very harmful to man, animals and vegetations.
Classification of Air Pollutants
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Air pollutants are broadly classified as
(a) According to origin
(b) According to chemical composition
(c) According to State of matter.
According to Origin
Air Pollutants can be classified as
(a) Primary Pollutants
(b) Secondary Pollutants
Primary Pollutants:- Primary pollutants are those which are
directly emitted from identifiable source
• These pollutants are emitted directly to the atmosphere.
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• e.g.
(a) Particulate matter
(b) Oxides of Sulphur
(c) Oxides of Nitrogen
(d) Carbon Monoxide
(e) Radioactive Compounds
• Secondary Air Pollutants:- Secondary air pollutants are those
which are produced in the air by the reaction of two or more
primary pollutants.
• e.g.
• Ozone
• Formaldehyde
• Photochemical smog
• Peroxy acetyl nitrate (PAN)
According to Chemical Composition
• All the air pollutants are classified as
(a) Organic Pollutants
(b) In Organic Pollutants
(a) Organic Pollutants:- Organic Pollutants contain carbon and
hydrogen.
e.g.
• Hydro Carbon
• Aldehyde and Ketones
• Alcohols
• Organic Sulphur compounds
• Inorganic Pollutants:- Inorganic compounds mainly includes
(a) Carbon monoxide (CO)
(b) Carbon dioxide (CO2)
(c)Carbonates
(d) Oxides of sulphur, nitrogen
(e) Ozone
According to State of Matter
• Air pollutants according to state of matter are classified as
(a) Natural Contaminants
(b) Particulate Matter
(c) Gases and Vapours
Natural Contaminants
• The air contaminants which are produced from natural sources
are called natural contaminants
• Eg. Pollen grains are emitted from weeds, grasses and trees
• This pollen grains are irritating to some individuals
• Size of pollen grains = 10 to 50 (µ)
Particulate matter
• These may be liquid or solid. The
particulate matter are identified
as aggregates which are larger
than 0.002 µ but smaller than 500
µ
Dust (1 To 10,000 µ) : Small solid
particles resulting from break up of
large masses through processes such
as crushing, grinding or blasting.
Smoke ( 0.5 To 1 µ) Consist of finely
divided solid particles produced by
incomplete combustion of organic
particles such as coal, wood, or
tobacco.
• Mist:- These are liquid particles formed by condensation of
vapor
• Fog (1 to 40 µ ):- High concentration of mist is called as fog. It is
dispersion of liquid particles in air.
• Fumes ( 0.03 to 0.3 µ ):- Fine solid particles formed by the
condensation of vapors of solid material. The fumes are
generally emit from melting operations.
• Ash ( 1 to 1000 µ ):- fine, noncombustible particles are known
as fly ash.
• Spray (10 to 1000 µ):- Liquid particles formed by automation
Gases And Vapors
• Carbon Monoxide:- (CO) This is an odorless, tasteless and
colorless gas formed due to incomplete combustion of
carbonaceous matter. The sources of carbon monoxide are
motor vehicles, burning of fossil fuel and industrial processes.
• Oxides of Sulphur:- They Include 4 different gaseous
compounds such as Sulfur monoxide ( SO), Sulfur dioxide ( SO2),
Sulphur trioxide ( SO3) and sulphur tetra oxide (SO4).
• Sulphur dioxide is a colorless, non flammable gas with
suffocating odor.
Oxides of Nitrogen
• Oxides of Nitrogen Include 4 gaseous compound:- Nitric oxide
( NO), Nitrogen dioxide (NO2), Nitrous Oxide (N) Nitrogen penta
oxide (N2O5)
• In air pollution, Nitric oxide (NO) and Nitrogen dioxide are of
prime concern. The sources of this pollutants are Industrial
Processes, automobile exhausts.
Hydrocarbon
• Organic compounds containing only carbon and hydrogen are
classified as Hydrocarbons.
• They are of 2 types.
• (a) Aliphatic hydrocarbon
• (b) Aromatic hydrocarbon
• Hydrocarbon present in the atmosphere in the atmosphere from
both natural and man made sources.
• The major sources of hydrocarbon is burning of gasoline and
industrial processes.
Effects of Some Common Air Pollutants
Particulate Matter:•
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Effects on human:The pollutants of size less than 1 µ causes lung damage
Asbestos fibers causes cancer
Lead from automobile exhaust affects brain
It causes several respiratory diseases
Silica , arsenic, dust causes cancer
Effects of air pollution on humans
• Effects on Plants:• Deposition of particulate matter containing toxic metals affects
the growth of plants
• The particulate matter after deposition on plant leaves block
stomata opening of plants and reduce plant growth.
• The particulate matter with acid rain, reduces pH of the soil
which makes the infertile.
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Effect on Material:
The particulate matter causes damage to building
The corrosion is enhanced
It causes cracks and fading of pointed surface
Particulates accumulate on the soil and reduces fertility of soil.
Carbon Monoxide
• Effects on humans:• The high concentration of CO can cause death
• The combination of CO and hemoglobin leads to the formation of
carboxylhaemoglobin (COHb) reduces the oxygen carrying
capacity of blood.
• At concentration of 100 ppm people experience dizziness and
headache.
• The cigarette smoke contains 400 to 450 ppm CO the percentage
of COHb in blood of cigarette smokers increases with increase in
smoking.
• At concentration of 750 ppm of CO it will cause death.
• Effects on plants:• CO reduces nitrogen fixing capacity of bacteria. Which affects
the plant growth.
• High concentration of causes leaf drops, reduces the size of leaf
and ageing
• Effects on materials:• Carbon monoxide appears to have no detrimental effect on
materials.
Oxides of Sulphur
• Effects on human health:• It causes irritation of eyes and respiratory tracts.
• Increase in SO2 concentration in the atmosphere, may lead to
lung cancer
• SO2 may obstruct breathing
• SO2 leads to the formation of H2 SO4 which is 20 times more
irritant than SO2
• Effects on Plants:• The low concentration for long period may cause discoloration
of leaves
• SO2 affects the growth of plants
• At high concentration the leaf tissues gets damaged.
• H2SO4 is extremely toxic to plants and soil fertility.
• Effects on Materials:• The sulphuric acid will attack building materials containing
carbonates. This will form CaSO4 the CaSO4 gets easily washed
away leaving discolored surface
• Paper absorb SO2 causing the paper to become brittle
• Leather looses the strength and flexibility.
Oxides of Nitrogen
• Effects on Human Health:- Nitric Oxide reduces the Oxygen
carrying capacity of blood.
• Nitrogen dioxide causes irritation of lungs
• High level of NOx causes pneumonia, lung cancer, oxygen
deficiency.
• NOx causes irritation of respiratory system, nervous system and
digestive tracts.
• NOx is extremely dangerous to human health.
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Effects on Vegetation:NO2 and primary pollutants can damage plant tissues
High concentration of NO Causes Damage to leaves.
Secondary Pollutants such as smog, O3 may damage the
vegetation
Effects on Materials:Nitric acid causes corrosion to metal surface
NO2 fades the color of clothes
NO2 causes cracking of rubber
Hydrocarbon
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Effects on human health:Aromatic hydrocarbon may lead to cancer
Inhalation of hydrocarbon causes irritation of respiratory tract.
Methane creates narcotic effects on human beings
Most of the hydrocarbon are carcinogenic to lungs
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Effects on Vegetation:HC affects plant growth
Discoloration of leaves
Effects on Materials:It causes discoloration of materials
Material becomes less elastic and more brittle.
Notations
• parts-per-million (ppm) 10–6, parts-per-billion (ppb) 10–9, and
parts-per-trillion (ppt) 10–12 level
Activity
• Enlist the air pollution episodes occurred
around the world in a chronological order.
Assignment
• Write a report on effects of air pollution on historical
monuments of archeological significance.
Thanks
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