Types of Pollution:

There are three main classes of the Environmental pollution:
(1) Air pollution :
The condition in which air contains harmful substances (chemicals, particulate matter or biological), gases, dust, fumes or odour in harmful amounts and causes discomfort to living beings and environment is called Air pollution.
Factors responsible for air pollution refer to the various activities or sources which are responsible for the releasing of pollutants into the atmosphere.

These sources can be classified into two major categories which are:

(a). Natural Factors/Sources:

The natural factors responsible for air pollution refer to the various activities or sources which occur naturally and are responsible for the releasing of pollutants into the atmosphere.

1. Volcanic Eruption:
On global scale most of the Suphurdioxide is produced by Volcanoes which is bout 67%. These volcanic eruptions are also responsible for Carbon Monoxide emission.

2. Bacterial Action:

Various bacterial actions produce Nitrogen Oxides, of which main is Nitrogen Monoxide.
Anaerobic decomposition of organic matter by bacteria in water sediments and in soils is the natural source of methane and methane.

3. Trees and Plants:

Large quantities of hydrocarbons are emitted by different trees and plants in the atmosphere. This methane can remain in atmosphere upto average 3-7 years.

(b). Anthropogenic Factors/sources:

The factors which contribute to air pollution due to human activity are called anthropogenic sources. Following are some factors:

1. Burning of different kinds of fuels:

Air pollution is cause by the injurious smoke emitted by automobiles, stacks of power plants, furnaces and incinerators and factories namely sulphur dioxide, carbon monoxide and nitrogen oxides. The emissions from vehicles are estimated to be responsible for approximately 60% of all air pollution alone The smoke from burning wood, dung and cigarettes is also harmful to the environment causing a lot of damage to man and the atmosphere.

2. Use of Paints and enamel:

The use of paint, varnish, aerosol sprays and other solvents has been common practice nowadays. This also causes generation of harmful off-gasing and unwanted fumes from things such as paint and plastic production which pollute natural air causing irritation.

3. Chlorofluorocarbons (CFC):

It is released from refrigerators, air-conditioners, deodorants and insect repellents and cause severe damage to the Earth’s environment. This gas has slowly damaged the atmosphere and depleted the ozone layer leading to global warming.

4. Waste deposition in landfills:

This process generates methane. Although methane is not much toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is also an asphyxiant and may displace oxygen in an enclosed space which may result in suffocation if the oxygen concentration is reduced to below 19.5% by displacement.

5. Military/Defence Military Practices:

Various military weapons and instruments like nuclear weapons, missiles, rockets, toxic gases, germ warfare etc used for defence and strategic purpose have also contributed to air pollution.