Which of the following is not a greenhouse gas?

Correct answer: (c) SO₂

Explanation

Sulphur dioxide (SO₂) is not a greenhouse gas. It forms sulphate aerosols, which reflect sunlight and have a slight cooling effect, and it is a main cause of acid rain.

The main greenhouse gases are carbon dioxide, methane, nitrous oxide (N₂O, also called laughing gas), the CFCs, HFCs and ozone in the lower atmosphere, together with water vapour.