Question

How is $S{O_2}$ an air pollutant?

Answer 1

Hint: Pollution is the presence of contaminants into the natural environment that cause adverse changes in the environment. It can take the form of chemical substance or energy, like, heat, light or noise. The components that cause pollution are called pollutants. These substances can be either foreign substances or energies or naturally occurring contaminants.

Complete step by step solution:
Sulphur dioxide $S{O_2}$ is mainly produced by the incomplete combustion of fossil fuels in automobiles and factories. It is an air pollutant because it has a very harmful effect on the environment as it can create pollutants such as particulate matter, sulfate aerosols and most harmful of this acid rain.
This sulphur dioxide $S{O_2}$ is the main cause of acid rain. It combines with the water droplets of rain and produces sulphuric acid, which rains on the environment and damages the surrounding.
Reaction associated is written below
\[S{O_2} + \dfrac{1}{2}{O_2} + {H_2}O \to {H_2}S{O_4}\]
This acid rain causes huge loss of environment such as, it damages the greenery, trees, biologically important herbs and shrubs. It completely burns them and also nearby ponds and lakes also get adversely affected by this as it changes the pH level of water which affects the biodiversity of that pond or lake causing aquatic life to die.
Acid rain caused by sulphur dioxide also affects the precious monuments for example: One of the seven wonders of the world, The Taj Mahal gets a serious effect as its white marble starts turning yellow in color. This acid rain reacts with calcium carbonate to make that yellowish appearance.
Additional Information: Sulphur dioxide is a colorless, bad smelling, toxic gas. It is also a natural byproduct of volcanic eruptions.
Acid rain is mainly caused by two main gases sulphur dioxide $S{O_2}$ and nitrogen oxides which are emitted from incomplete combustion of fuels.

Note: Sulphur dioxide is not acid rain. It is the reactant that combines with water in the atmosphere to form sulphuric acid that causes acid rain. Sulphur dioxide is that toxic gas which is responsible for the smell of burnt matches.