Question

Explain the difference between pure air and polluted air? [2 marks]

Answer 1

$\bullet$ The composition of pure air contains 78% nitrogen, 21% oxygen, and 0.03% carbon dioxide. Besides these, there are some other gases like methane, argon, and water vapour. [1 mark]
$\bullet$ The air is said to be polluted when the composition of air is altered by the addition of harmful substances or gases such as sulphur dioxide, carbon monoxide, nitrogen dioxide, and particulate matter. [1 mark]