Question

1. which of the following is categorized as a secondary air pollutant?

a. lead
c. benzene
b. atmospheric acids
d. gasoline vapors

Explanation:

To determine the secondary air pollutant, we recall: Primary pollutants are emitted directly (e.g., lead, benzene, gasoline vapors). Secondary pollutants form in the atmosphere from primary pollutants. Atmospheric acids (like sulfuric or nitric acid) form from reactions of primary pollutants (e.g., $SO_2$, $NO_x$) with other substances in the air, so they are secondary. Lead, benzene, and gasoline vapors are emitted directly (primary).

Answer:

b. atmospheric acids