Which one among the following is not a greenhouse gas?

Greenhouse gases (GHGs) are atmospheric gases that absorb infrared radiation and contribute to global warming. The primary GHGs include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) [5]. Additionally, synthetic fluorinated gases such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6) are recognized as potent GHGs under international frameworks like the Kyoto Protocol [3]. While sulfur dioxide (SO2) is a significant atmospheric pollutant derived from industrial processes and natural sources, it is not classified as a greenhouse gas [2]. Instead, SO2 often acts as a precursor to aerosols that can have a cooling effect on the climate by reflecting solar radiation, unlike GHGs which trap heat [4]. Therefore, among the given options, sulfur dioxide is the only one that is not a greenhouse gas.

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 29: Environment Issues and Health Effects > Greenhouse gases (GHGS) > p. 426
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > 20.1. Composition of The Earth's Atmosphere > p. 270
3. [5] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Biotic: Living > p. 111
4. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 17: Climate Change > qA.S. Fluorinated Gases > p. 257
5. [4] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 11: World Climate and Climate Change > Greenhouse Gases(GHGs) > p. 96