Question

Air pollution is the contamination of air by pollutants. In this context answer the following:

Based on their origin, how can air pollutants be classified?

Answer 1

1. Primary Pollutants: These pollutants are directly emitted from a source into the atmosphere. Examples include carbon monoxide (CO) from vehicle exhaust, sulfur dioxide (SO₂) from industrial processes, and particulate matter (PM) from construction or burning of materials.
2. Secondary Pollutants: These pollutants are not emitted directly but are formed through chemical reactions in the atmosphere from primary pollutants. Examples include ozone (O₃) and smog, which are formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with sunlight.