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

Explanation

The following are the reasons for `SO_(2)` to act as an air pollutant: (i) `SO_(2)` strongly affects the respiratory tract causing irritation of throat and eyes, at a concentration of 5 ppm. It causes cough, tears and redness in the eyes, breath lessness and affects the larynx. (ii) At a much lower concentration of 0.03 ppm, `SO_(2)` has a damaging effect on the plants. On prolonged exposure, the formation of chlorophyll slows down leading to chlorosis in leaves where the leaves lose their green colour and cannot perform photosynthesis (iii) `SO_(2)` dissolves in rain water and produces acid rain, which damages building materials, especially marble `(CaCO_(3))`.
`CaCO_(3)+H_(2)SO_(3)toCaSO_(3)+H_(2)O+CO_(2)`
Metals like iron and steel are easily corroded by `SO_(2)` . It also causes deterioration of leather, paper, etc.