Photochemical smog occurs in

Photochemical smog, also known as Los Angeles smog or summer smog, is a type of air pollution that occurs primarily in warm, dry, and sunny climates. It is formed through the interaction of ultraviolet light from the sun with primary pollutants like nitrogen oxides (NOx) and volatile organic compounds (VOCs), which are largely emitted from vehicle exhausts [2]. Sunlight triggers complex chemical reactions that produce secondary pollutants such as ground-level ozone and peroxyacetyl nitrate (PAN) [2]. High temperatures accelerate these reactions, while calm winds and temperature inversions trap the pollutants near the ground [1]. In contrast, classical smog (industrial smog) typically occurs in cool and humid climates and is characterized by high concentrations of sulfur oxides and smoke. Therefore, the intense solar radiation and lack of precipitation in warm, dry regions provide the ideal conditions for photochemical smog formation.

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Y{r7 $ EilVIAONMEHT > p. 65
2. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Biotic: Living > p. 117