Question

How can photochemical smog be controlled?

• A. By using catalytic convertors in the automobiles/industry.
• B. By complete combustion of fuel.
• C. By using catalyst.
• D. By using tall chimneys.

Hint:

To control photochemical smog, reducing emissions of nitrogen oxides (NOx) and volatile organic compounds (VOCs) using catalytic converters is the most effec tive solution.

Answer 1

The Correct Option is A

Photochemical smog is a type of air pollution that occurs when sunlight reacts with pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs). These pollutants are primarily emitted from automobiles and industrial processes. The smog contains harmful substances like ozone (\( \text{O}_3 \)) and peroxyacetyl nitrates (PANs), which can harm human health and the environment.

The most effective way to control photochemical smog is to reduce the emissions of these harmful pollutants. The use of catalytic converters in automobiles and industrial exhaust systems helps to reduce the emissions of nitrogen oxides (NOx) and hydrocarbons (VOCs) that contribute to photochemical smog formation. Catalytic converters work by promoting chemical reactions that convert these pollutants into less harmful substances, such as nitrogen (\( \text{N}_2 \)), carbon dioxide (\( \text{CO}_2 \)), and water (\( \text{H}_2\text{O} \)).

1. Option (1): Using tall chimneys may help disperse pollutants over a larger area, but it does not address the root cause of photochemical smog. Hence, this option is ineffective.
2. Option (2): Complete combustion of fuel can reduce the production of particulate matter and some gases, but it does not fully prevent the formation of nitrogen oxides and volatile organic compounds that cause photochemical smog.
3. Option (3): Catalytic converters are specifically designed to reduce the emissions of harmful pollutants such as nitrogen oxides and hydrocarbons, which are major contributors to photochemical smog. Hence, this option is the most effective.
4. Option (4): While catalysts are used in catalytic converters, using a catalyst alone without addressing the emissions is insufficient to control photochemical smog.

Conclusion: The correct answer is 1.