(a) What is air? Write the names of various constituents of air. (b) What is air pollution? What are the main sources of air pollution?
ScienceClass 8ICSEAnswered 28 Mar 2026
Answer
(a) Pure air is a mixture of several gases that are invisible and odourless. It consists of about 78% nitrogen, 21% is oxygen and less than 1% of Carbon dioxide and other gases like argon, methane and ozone and a varying amount of water vapours.
(b) Air pollution is the contamination of fresh air by unwanted substances like dust smoke and other chemicals emitted from industries and factories.
Main sources are:
- Smoke and dust arising from the forest fire
- From automobile exhausts, factories and burning of woods
- The pollutants like Sulphur dioxide and Nitrogen dioxide causes acid rain
- Carbon monoxide from fuels like petrol and
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