Air pollution and it's sources

AIR POLLUTION

 Air pollution is defined  because the excessive concentration of foreign matter within the air

which adversely affects the well-being of individual or causes damage to the property. It also affect plants, animals and other things

Watch videoControl of air pollution

Sources of air pollution:-

Natural sources 

Man-made sources 

Natural sources  of air pollution:-

Products from atmospheric reactions

(chemical reactions like oxidation,

combination, polymerization,

photochemical reactions etc.)

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2. Aerosols-Particulates: Aerosols are

finely divided solid or liquid particles of

micro scopic size held suspended and

dispersed in atmosphere. They cause

visibility reduction, soiling of surfaces,

corrosion etc.

The various types of aerosols are

(a) dust, (b) smoke, (c) mists, (d) fog,

(e) haze, (f) fumes.

3. Micro-organisms: Infect plants and

animals.

4. Pollens: Pollens are the small grains

from the anthers of flowers which may

cause allergic reaction.

5. Radioactive minerals:

Eg. Uranium

6. Volcanic ash and gases

7. Gases and odour from marshy lands.

MAN-MADE SOURCES OF AIR POLLUTION

Results due to human being

1) combustion of fuels in automobiles

Eg. CO2,SO2, etc

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2) industries emit undesirable gases

Eg. (SO2 ,CO2 ,NO2 ,NH3 ,CO)

3) Thermal Power Plants: Mainly they

emit Sulphur dioxide.

4) Automobiles: Exhaust contains carbon

monoxide (CO), methane, un-burnt

carbon. CO is the main source of air

pollution in congested cities.

v) Agricultural activities: Crop spraying

and field burning.

vi) Nuclear Power Plants: Emit various

radioactive substances.

Also read Solid waste management

Types of air pollutants:-

Substance responsible for air pollution is known as air pollutants,they are of two types

i) Primary air pollutants, and

ii) Secondary air pollutants.

Primary air pollutants are those which 

are results of natural phenomenon

E.g.: Particulate matter such as dust and

aerosols,

 Pollens

 Sulphur compounds (SO2,SO3,H2S ) 

 Nitrogen compounds (NO2,NO ,NH3) 

 Carbon monoxide (CO) and carbon

dioxide (CO2)

 Photochemical oxidants

lead

Hydrocarbons

 Radioactive materials

 Halogen compounds

Read Types of bacteria

Secondary air pollutants

Those pollutants which are formed in the atmosphere by reactions between two or more primary air pollutants.

Eg.

1. Sulphuric acid(H2SO4)

Sulphuric acid (H2SO4) is formed by 

simple chemical reaction between sulphur 

dioxide (SO2) and water (H2O) vapour. It causes acid rains.

2. Ozone(O3)

3. Formaldehyde

4. Peroxy-acetyl-nitrate(PAN)

5. Photochemical smog 

2,3,4&5 etc., are formed by photochemical 

reactions caused by sunlight between two 

primary pollutants.

Features of air pollutants

Sulphur dioxide (SO2):

It is among the foremost important air pollutant and exists where ever fossil fuels are burnt. Thermal plants produce the largest quantity of SO2

Carbon Monoxide (CO):

The automobile exhausts are the main contributors CO. 

The (CO) causes asphyxia i.e., loss of consciousness as a result of too little oxygen and too much carbon dioxide in the human blood.
Hydrocarbons and Photochemical oxidations:
Hydrocarbons are generally released in the atmosphere by car exhausts.

Lead:-

It is mainly injected into the atmosphere from the car exhausts particularly by the automobiles running on petrol. 

They cause irritation of mucous membranes of nose, throat and lungs.

Oxides if nitrogen:

It is most largest pollutants of air in large cities  after SO2
The oxides of nitrogen are produced from air oxidation, discharge and solar radiations, incineration plants, welding operation etc.

Next blog on effects and control of air pollution