Air is one of five basic natural ingredients of life system and also an inexhaustible natural resource. It is very essential for the survival of all the living organisms on earth. Air is a mixture of different gases; nitrogen, carbon and oxygen are the major components. Besides, the above mentioned gases, small quantities of hydrogen, ozone, Nobel gases, oxides of nitrogen & sulphur, carbon monoxide, other organic and inorganic gases, aerosols and particulates which are emitted by various sources are dispersed in the atmosphere through diffusion. The normal composition of total volume of clean air present in atmosphere is as under:
Atmosphere is a dynamic system that continuously receives a wide range of solids, liquids and gasses from both natural and anthropogenic sources. Further, introduction of chemicals, particulate matter, or biological materials harmful to human beings or other living organisms or which damage the natural environment cause pollution.
Air quality is a measure of the condition of air relative to the requirements of one or more biotic species or to any human need or purpose. Various contaminants continuously enter the atmosphere through natural and man-made processes and these contaminants interact with the environment to cause disease, toxicity, environmental decay etc. and are labelled as pollutant.
Air pollutants from different sources
| S.No. | Sources of Emissions | Air Pollutants | |
|
| 1. | Industrial Emissions | Oxides of Carbon, Sulfur & Nitrogen, Particulate Matter, Ozone, Nickel, Lead etc. | |
| 2. | Vehicular Emissions | Oxides of Nitrogen, Particulate Matter, Ozone, Ammonia, Benzene, Arsenic, BaP | |
| 3. | Burning of Garbage and Biomass | Oxides of Carbon & Nitrogen, Particulate Matter Particulate Matter, BaP, Nickel | |
| 4. | Pollution from Road Dust | Particulate Matter | |
| 5. | Pollution from DG sets | Oxides of Carbon & Nitrogen, Particulate Matter, Benzene, Arsenic | |
| 6. | Construction and Demolition Activities | Particulate Matter | |