Photochemical smog formation in urban areas is mainly due to the presence in the atmosphere of.

Correct option is C

Explanation of the Correct Option (c): Particulates and fog
· Photochemical smog is a type of urban smog.
· It forms when:
· Pollutants interact in the presence of sunlight
· Fine particulate matter combines with atmospheric moisture (fog)
· Particulates act as condensation nuclei, enhancing smog formation.
· Urban areas with high vehicular emissions often have:
· Suspended particulate matter
· Atmospheric moisture
· Hence, the presence of particulates and fog plays a major role in smog formation in cities.
Explanation of Other Options
Option (a): Ozone, PAN, and Nitrogen dioxide
· Incorrect because:
· These are components or products of photochemical smog.
· They are not the primary atmospheric condition causing its formation.
Option (b): Fog and Smoke
· Incorrect because:
· Refers more to classical (London) smog, not photochemical smog.
Option (d): Winter climate and high humidity
· Incorrect because:
· Photochemical smog is common in sunny, warm conditions, not winter.
Key Points:
· Photochemical smog is also called Los Angeles smog
· Forms in presence of sunlight, NOx, hydrocarbons
· Common in urban and industrial regions
· Major health impacts on eyes and respiratory system