Question

Write a short note on Photochemical smog.

Answer 1

Photochemical smog is a type of air pollution characterized by a complex mixture of pollutants formed through photochemical reactions in the presence of sunlight. It primarily results from the interaction of nitrogen oxides (NOx) and hydrocarbons emitted by automobile exhaust and industrial sources. When these primary pollutants are exposed to sunlight, they undergo a series of reactions producing secondary pollutants such as ozone (O₃), peroxyacyl nitrates (PAN), hydrogen peroxide (H₂O₂), organic peroxides, and other oxidizing compounds. This smog is highly oxidizing and is known to cause respiratory problems, eye irritation, and other health hazards.

The formation of photochemical smog involves nitrogen oxides from combustion engines reacting with hydrocarbons and sunlight to produce ozone and other secondary pollutants. The ozone thus formed is a major component of photochemical smog and contributes to its harmful effects on human health and vegetation.