Which among the following is not a greenhouse gas?

Greenhouse gases are gases in Earth's atmosphere that trap heat and energy. The sunlight pass through the atmosphere, but it is due to these greenhouse gases that they prevent the heat that the sunlight brings from leaving the atmosphere examples for greenhouse gases are: Carbon dioxides, Methane, water vapour, etc.

But some gases are responsible for air pollution and acid rain and contaminate environment these are primarily chlorofluorocarbons, sulphur dioxide. 

Hence, we conclude that sulphur dioxide is not a greenhouse gas.