Air pollution is complex in origin and varied in effect. It is very crucial from the point of human health. Every human being inhales about 15-22 kg of air daily and air is polluted, one can easily imagine the, damage it can cause to human health. This problem is generally associated with industrial revolution; population explosion and revolution in automobiles industry. The release of poisonous gases like CO, N₂O and combustion products from industries and automobiles disturb the balance among the air components such as N2 =78.09%, O₂ =20.94%. CO₂ = 0.03%, water vapour = 1-5% etc. besides these, there are natural sources of pollution such as volcanic eruptions, dust, storm, forest fires etc. all this is making environment detrimental for living organisms. Air pollution may be defined as "the presence of various harmful substances in such a concentration into the air which are harmful to man and environment".

In other words "the addition of foreign particles, gases and other pollutants into the air in quantities and duration that have adverse effects on human beings, animals, vegetation, buildings and other object is called air pollution".