Question

Which one of the following is primary pollutant?

Options

• SO₂

• CO

• NO₂

• All of these

Answer 1

All of these

Explanation:

SO₂ (sulphur dioxide), CO (carbon monoxide), and NO₂ (nitrogen dioxide) are all primary pollutants because they are directly emitted from sources such as automobile exhausts, combustion of fossil fuels, and industrial processes. Primary pollutants are those that are directly released into the atmosphere in a harmful form before undergoing any chemical transformation.