Photochemical Smog Formation
Question
Photochemical smog is a resultant of the reaction among (a) NO_2, O_3 and peroxyacetyl nitrate in the presence of sunlight (b) CO, O_2 and peroxyacetyl nitrate in the presence of sunlight (c) CO, CO_2 and NO_2 at low temperature (d) high concentration of NO_2, O_3 and CO in the evening
Options
NO_2, O_3 and peroxyacetyl nitrate in the presence of sunlight
CO, O_2 and peroxyacetyl nitrate in the presence of sunlight
CO, CO_2 and NO_2 at low temperature
high concentration of NO_2, O_3 and CO in the evening
Explanation
Photochemical smog forms through complex chemical reactions initiated by UV radiation from sunlight. The primary reactants are nitrogen oxides (particularly NO₂) and volatile organic compounds (VOCs), which produce secondary pollutants including ozone (O₃) and peroxyacetyl nitrate (PAN). These reactions require sunlight energy, occurring primarily during daytime. Option (b) incorrectly includes CO and O₂. Option (c) specifies low temperature and no sunlight, which is incorrect. Option (d) specifies evening when photochemical reactions are minimal. Photochemical smog is fundamentally a daytime phenomenon driven by solar radiation. > Photochemical Smog = NO₂ + VOCs + Sunlight → O₃ + PAN. Answer: (a).
Question details
Year
2014
Paper
GS Paper 1
Question
Q49
Subject
Environment
Sub-topic
Air Pollution
Type
Factual single
Difficulty
Medium
Nature
Static
Source hint
NCERT Environmental Science - Air Pollution
See all questions on Air Pollution
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