Question

Brown air is due to:

• A. CO₂
• B. SO₂
• C. CH₄
• D. NO_x

Hint:

To prevent the formation of brown air, reducing emissions from vehicles and industrial sources that release NOx and VOCs is essential, along with promoting cleaner technologies and fuels.

Answer 1

The Correct Option is D

The phenomenon of "brown air" is primarily associated with the presence of nitrogen oxides, commonly represented as NO_x. These compounds are significant air pollutants produced from combustion processes, such as those occurring in vehicles and industrial operations. NO_x gases lead to the formation of photochemical smog, characterized by its brownish hue. This occurs when sunlight triggers a series of chemical reactions between NO_x and other volatile organic compounds. The result is the generation of pollutants like ozone (O₃) that contribute to smog's characteristic coloration.

Incorrect options:

• CO₂: Carbon dioxide is a colorless gas primarily associated with global warming, not directly with brown air.
• SO₂: Sulfur dioxide can cause haze but does not cause brown air on its own.
• CH₄: Methane is a potent greenhouse gas but not linked to the coloration of air.

Therefore, the correct answer is NO_x, responsible for the formation of brown air due to its role in creating photochemical smog.