Answer: It has a global warming potential about 298 times that of CO 2 over a 100-year period.
- A It is the most abundant greenhouse gas by volume in the atmosphere
- B It has a global warming potential about 298 times that of CO<sub>2</sub> over a 100-year period
- C It reacts directly with tropospheric ozone, worsening urban smog
- D It is uniquely soluble in water and falls as acid rain, acidifying aquatic ecosystems
Correct answer: B. It has a global warming potential about 298 times that of CO<sub>2</sub> over a 100-year period
Explanation: N<sub>2</sub>O has a GWP of approximately 298 times CO<sub>2</sub> over 100 years, making it the third most important greenhouse gas by radiative forcing despite low concentrations. Its main anthropogenic sources are nitrogen fertilisers and livestock manure. It also destroys stratospheric ozone by reacting with O atoms to produce NO.
Classical smog is a reducing mixture of SO₂ and fog, while photochemical smog is an oxidising mixture generated by UV-driven reactions of NOx and hydrocarbons.
Concept context
Understand how human activities alter the atmosphere, water, and soil. Covers air pollutants, smog types, ozone depletion, acid rain, greenhouse effect, water and soil pollution, and the principles of green chemistry.