Multiple choice

Which of the following is a secondary pollutant?

  1. PAN

  2. SO3

  3. SO2

  4. NO2

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

Secondary pollutants are formed by reaction among primary pollutants. PAN (Peroxyacetyl nitrates) are formed through the reaction between nitrogen oxides and hydrocarbons in the presence of sunlight.