environment medium MCQ

Which of the following is a primary component of photochemical smog?

  1. Sulphur dioxide
  2. Ground-level ozone
  3. Carbon monoxide
  4. Particulate matter only

Answer: Ground-level ozone

Photochemical smog forms when sunlight triggers reactions between NOx and VOCs, producing ozone, PAN, and other secondary pollutants harmful to health.

Topic Environmental Chemistry
Exam Relevance UPSC, SSC