It is controlled by the use of catalytic converters in automobiles.

It causes corrosion of metals.

It is a mixture of $\mathrm{SO}_2$, smoke and fog.

It causes extensive damage to plant life.

$\mathrm{SO}_4^{2-}$

$\mathrm{NO}_3^{-}$

$\mathrm{F}^{-}$

Pb

A-IV, B-III, C-II, D-I

A-IV, B-III, C-I, D-II

A-III, B-IV, C-I, D-II

A-II, B-III, C-IV, D-I

$\mathrm{CH}_4$

$\mathrm{CFCl}_3$

NO

$\mathrm{Cl}_2$