Multiple choice

What is smog?

  1. Bacteria in the air

  2. ozone in the troposhere

  3. CFCs

  4. All of the above

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Smog is primarily ground-level ozone formed by chemical reactions between sunlight and pollutants like nitrogen oxides and volatile organic compounds. It is not bacteria or directly CFCs.