Air Pollution: The industrial revolution and infrastructure development is associated with economical progress of a country but it is also responsible for making the earth’s environment inhospitable for future generations. The release of unwanted gases like nitrous oxide, carbon monoxide and carbon dioxide from industries and automobiles disturb the balance among the air components. These foreign particles pollute the air which is not suitable for non-living and living organisms on earth.
The air pollution may be defined as the presence of one or more unwanted contaminants like smoke, mist, fumes, dust, vapor etc in air which deteriorates the quality of air.
Sources of air pollution:
The main sources of air pollution can be classified as
1. Stationary sources:
a. Point sources: Smoke from power plants, Solid waste disposal, Industrial fuel combustion (Coal and Oil).
b. Area sources: Residential area, Industrial areas and open burning sites
2. Mobile sources:
a. Line sources: Exhaust pollution from vehicles on highways, locomotives and railroads.
b. Area sources: Light duty and Motor vehicles in city, Air crafts on Airports, Rail yard locomotive
Growth in population is a major problem.
Classification of air pollutants:
The air pollutants are classified into three categories
Classifications based on existence in nature:
Qualitative pollutants: These substances do not occur naturally in nature but are added by human beings and are polluting by their vary existence. Example Insecticides and Pesticides.
Quantitative pollutants: Those substances which normally occur in the environment by acquire the status of pollutants when their concentration increases due to human activities. Example Carbon dioxide is as present in the nature but when its quantity increases it acts as a pollutant referred to as quantitative pollutant.
Classification based on the form in which they persist:
Primary pollutant: These are those which are directly emitted from the source and persist in the form in which they are released in the atmosphere. Example smoke, sulphur dioxide and nitric oxide.
Secondary pollutant: These are the ones which are formed from primary pollutants by chemical interaction with certain constituents present in the nature. Example smog, sulphur trioxide, nitrogen dioxide and ozone.
Classification based on degradation:
Bio-degradable: These are the pollutants which are degraded by either natural (Example domestic sewage) means or engineered systems (Treatment plant based).
Non bio-degradable: These are the ones which do not degrade or degrade very slowly in nature. Example Aluminum cans and DDT.
Effects of air pollution
On human beings:
1. Symptoms such as headache, coughing and throat infection.
2. Reduces the oxygen carrying capacity of blood.
3. It can cause respiratory diseases.
4. Depletion in ozone layer which can lead to skin cancer
On plants and animals:
1. Reduction in yield from cattle.
2. Dropping of leaves from trees.
3. Reduction in Chlorophyll.
4. Killing of tissues
Deforestation
Clearing of forests and using that land for agricultural, residential or commercial purposes is called deforestation. Forest fires and severe droughts are also some of the natural reasons of deforestation.
Consequences of deforestation:
- Pollution level increases due to increase in the level of carbon dioxide in the atmosphere.
- Chances of natural calamities such as floods and droughts increase.
- Ground water level gets lowered.
- Fertility of soil decreases and gradually the fertile land gets converted into deserts. This process is called desertification.
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