How is `SO_(2)` an air pollutant ?

Explanation

(i) Sulphur dioxide released in the atmosphere during the combustion of fuels combines with `H_(2)O` molecules and oxygen present to form sulphuric acid. The acid being posonous in
`SO_(2)+1//2O_(2)+H_(2)O to H_(2)SO_(4)`
nature causes pollution. It causes the corrosion of statues and monuments made from marble `(CaCO_(3))` due to the formation of sulphate.
`CaCO_(3)+H_(2)SO_(4) to CaSO_(4)+H_(2)O+CO_(2)`
(ii) Sulphur dioxide adversely affects respiratory tract due to its poisonous as well as irritating nature. It causes throat infection as well as irritation in the eyes.
(iii) Even very low concentration of the gas (0.03 ppm) has a very damaging effect on plants and vegetation. This is called chlorosis. It slows down the formation of chlorophyll and the leaves slowly wither.