Question

Which of the following are Green House Gases (GHGs) which are responsible for warming of the Earth?
A. Ozone
B. $H_2O$ Vapour
C. Carbon Tetrachloride
D. Nitrogen Dioxide
E. Methane

• A. A, D and E Only
• B. A, B, C, D and E
• C. A, C, D and E Only
• D. A, B, C and E Only

Hint:

Don't confuse $NO_2$ with $N_2O$. Nitrous Oxide ($N_2O$) is a powerful greenhouse gas (laughing gas), but Nitrogen Dioxide ($NO_2$) is a reddish-brown toxic gas mainly known for causing smog.

Answer 1

The Correct Option is D

Concept: Greenhouse gases are gases in Earth's atmosphere that trap heat. They allow sunlight to pass through the atmosphere but prevent the heat that the sunlight brings from leaving the atmosphere.

Step 1: Identifying valid GHGs.

• B. Water Vapour ($H_2O$): The most abundant natural GHG.
• E. Methane ($CH_4$): A potent GHG released during agricultural and industrial activities.
• A. Ozone ($O_3$): Tropospheric ozone acts as a GHG.
• C. Carbon Tetrachloride ($CCl_4$): A man-made ozone-depleting substance that also has significant global warming potential.

Step 2: Excluding non-GHGs.
Nitrogen Dioxide ($NO_2$) is an air pollutant (part of $NO_x$), but it is not typically classified as a major direct greenhouse gas in the same way as Nitrous Oxide ($N_2O$). Direct warming is primarily caused by $CO_2, CH_4, N_2O$, Water Vapour, and CFCs.