Question

What is air pollution? What are the harmful effects of sulphur dioxide, nitrogen dioxide and hydrogen sulphide present in the air?

Answer 1

Air pollution is an excessive amount of harmful substances present in the air around us. It can be described as the change in quality of the air by chemical processes due to various pollutants present in the air. The main source of air pollution are some gases like carbon dioxide, methane, Chlorofluorocarbon (CFC) etc

Complete answer:
Air pollutants are the substances which are responsible for air pollution. There are different types of air pollutants. Gases mentioned in the question are also air pollutants. Let us discuss the effect of each one of them on air.
Sulphur dioxide: Sulphur dioxide is a toxic gas. The chemical formula of Sulphur dioxide is $S{O_2}$. The main source of sulphur dioxide is burning of coal and oil in power plants. Sulphur dioxide forms acidic substances in the air which are responsible for the acid rain.
Nitrogen Dioxide: Nitrogen dioxide is a gas with reddish-brown colour. The chemical formula of the Nitrogen dioxide is $N{O_2}$. It is generally released in air due to combustion of fossil fuels. It is responsible for making other air pollutants like ozone and particulate matter.
Hydrogen Sulphide: Hydrogen sulphide is also a gas, it is colourless and has a rotten-egg-like smell. Chemical formula of hydrogen sulphide ${H_2}S$. It is formed by the decomposition of organic material such as decaying plant material.

Note:
Hydrogen sulphide is highly toxic and extremely flammable. It causes headache and pain in the eyes when it is present in low concentration in the air. Higher concentration of Hydrogen sulphide in air can cause death.