Which one of the following is not an air pollutant?

Correct option is D

N₂O (Nitrous oxide) is not considered a primary air pollutant in the context of urban air quality. While it is a greenhouse gas contributing to climate change, it is not directly harmful to respiratory health like other nitrogen oxides.
Information Booster: · Primary air pollutants include substances directly emitted into the atmosphere (e.g., NO, CO, SO₂).
· NOₓ pollutants are major contributors to photochemical smog and acid rain.
· N₂O is a significant greenhouse gas with a global warming potential much higher than CO₂.
· Nitrogen oxides are regulated as air pollutants due to their direct impact on health and the environment.
· Greenhouse gases like N₂O are categorized under climate change impacts, not air pollution.
Additional Knowledge: · (a) NO: A reactive gas released from combustion processes. It plays a key role in forming NO₂ and ozone.
· (b) NO₂: A harmful gas causing lung irritation and reduced immune defense against respiratory infections.
· (c) NOₓ: A group of gases, primarily NO and NO₂, involved in environmental issues like acid rain and ozone formation.