Air pollution is the presence of materials in the air in such concentration which are harmful to man and his environment. In other words, air pollution is the occurrence of foreign particles, gases and other pollutants in the air which have an adverse effect on human beings, animals, plants and buildings.
Air pollution is caused by various sources. These are:
- The combustion of fuels such as natural gas, petroleum, coal and wood in industries, automobiles, kitchens and thermal power stations pollute the air.
- Mining and metallurgical processing of metals cause air pollution.
- Various agricultural activities such as use of pesticides, weedicides, fungicides and fertilizers cause air pollution.
- Chemical industries also pollute air by releasing a number of harmful gases such as carbon monoxide, carbon dioxide, sulphur dioxide, oxides of nitrogen, chlorine gas, lead etc.
- Large scale cutting of trees has led to air pollution by increasing the amount of carbon dioxide in air.
- The use of aerosols such as chlorofluorocarbons (CFCs) in refrigerators, air-conditioners, fire extinguishers and aerosol sprayers also cause air pollution by depleting the ozone layer present in upper atmosphere.
- Various industrial processes such as stone crushing, blasting, drilling and grinding also cause air pollution.
- Various natural processes such as decomposition of organic matter, volcanic eruptions, dust storms, forest fires and electric storms are also major source of air pollution.