1. The document discusses air pollution and defines it as the presence of unwanted particles and gases in the air that can adversely affect humans, animals, plants, and structures.
2. It describes the composition of air and structure of the atmosphere, which is divided into different layers including the troposphere, stratosphere, mesosphere, and thermosphere.
3. The major sources of air pollution are discussed as natural sources like volcanic eruptions and man-made sources such as automobile exhaust, industries, and agricultural activities. Common air pollutants like particulate matter, carbon monoxide, oxides of sulfur, oxides of nitrogen, and hydrocarbons are described along with their sources and effects on
2. AIR POLLUTION
Air pollution is defined as the presence of unwanted and undesirable foreign
particles and gases in the air which ay have adverse effects on human beings,
animals,plants,vegetations and important structures.
POLLUTANT
Any substance present in the environment in harmful concentration which adversely
alters the environment by damaging the growth rate of a species and by interfering
with the food chains is toxic and affects the health, comfort and property etc. is
considered as a pollutant.
4. 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
5. 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.
6. 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.
8. AMBIENT AIR QUALITY
STANDARDS
* Ministry of Environment and Forests, Government of India notification,1994
** Particle size less than 10 µm
9. CLASSIFICATION OF AIR
POLLUTANTS
Air pollutants
Based on Origin
Based on states of
matter
Based on presence in
environment
Particulate
air pollutants
Gaseous air
pollutants
Secondary
air
pollutants
Primary air
pollutants
Indoor air
pollutants
Outdoor air
pollutants
10. ACCORDING TO ORIGIN
(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.
e.g.
(a) Particulate matter
(b) Oxides of Sulphur
(c) Oxides of Nitrogen
(d) Carbon Monoxide
(e) Radioactive Compounds
11. 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)
12. CLASSIFICATION BASED ON
STATES OF MATTER
1. Gaseous air pollutants
2. Particulate air pollutants
GASEOUS AIR POLLUTANTS
Gaseous air pollutants are those air pollutants which are found in the gaseous state at
normal temperature and pressure in the atmosphere.
The most common gaseous air pollutants are:
Carbon monoxide
Carbon dioxide
Nitrogen oxides
Sulpher oxides
Hydrocarbons etc.
13. PARTICULATE AIR POLLUTANTS
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 ( 0.1 To 10 µm) :- 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.
14. CLASSIFICATION BASED ON
PRESENCE IN ENVIRONMENT
1. Indoor air pollutants
2. Outdoor air pollutants
INDOOR AIR POLLUTANTS
The air pollutants which are generated from households are called indoor air
pollutants.
Cleaning agents
Mosquito repellents
Pesticides
Cigarette smoke
Gases from stoves etc.
15. Outdoor air pollutants
The air pollutants which are generated outside the buildings are called outdoor air
pollutants.
Automobile pollutants
Industrial pollutants
Mining pollutants
Natural emissions from decaying matter and animals etc.
16. SOURCES OF AIR POLLUTION
The sources of air pollution may be classified into two groups:
1. Natural sources
2. Man made sources
NATURAL SOURCES
The following are the different forms of natural sources:
Atmospheric reactions
Volcanic eruptions
Forest fires
Dust storms, electric storms
Salt spray form oceans
Microorganisms
Radioactive substances
17. Man made sources
Combustion of fuel
Automobile exhaust
Industries
Thermal and nuclear power plants
Agricultural activities
Construction materials
System of sanitation
Mining
Nuclear explosions
Air crafts
Waste water treatment plants
18. MAJOR AIR POLLUTANTS –
SOURCES AND EFFECTS
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.
19. 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.
20. EFFECTS OF SOME COMMON
AIR POLLUTANTS
Particulate Matter:-
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
22. 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.
23. 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.
24. 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.
25. 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.
26. 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.
27. 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.
28. 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.
29. 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
30. HYDROCARBON
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
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.