Distinguish between primary and secondary air pollutants.

Explanation

Air pollutions can be classified as:
Primary pollutants:. The pollutants which are given out directly from the sources. The toxic gases like sulphur dioxide, carbon monoxide, oxides of nitrogen, hydrogen sulphide, hydrocarbons etc. The particulate matters like smoke, dust fumes, ash and metal particulates etc. are some of the examples of primary pollutants.
Secondary pollutants: The pollutants which are formed due to chemical reactions (mainly by oxidation, dissociation and dissolution) involving primary pollutants. Sulphur trioxide, nitrogen dioxide, sulphuric acid, nitric acid are some of the examples of secondary pollutants.