Question

Which of the following statements about primary pollutants are true?

1. They are emitted directly into the atmosphere.

2. Carbon monoxide and DDT are primary pollutants.

3. They are more toxic than secondary pollutants.

• A. 1 & 2
• B. 2 & 3
• C. 1 & 3
• D. All are correct

Answer 1

Answer:

A. 1 & 2

• Correct Answer: Option A) 1 & 2

• Primary pollutants are substances that are released directly into the atmosphere from sources and maintain their form.

• They are emitted directly into the atmosphere - This statement is True. Primary pollutants are, by definition, emitted directly into the environment from identifiable sources such as vehicle exhausts, factory chimneys, forest fires, etc.

• Carbon monoxide and DDT are primary pollutants - This statement is True. Carbon monoxide (CO) is released directly from incomplete combustion processes like vehicle engines and industrial operations. DDT (dichlorodiphenyltrichloroethane) is a pesticide that was directly applied to the environment and enters the atmosphere through spraying.

• They are more toxic than secondary pollutants - This statement is False. Toxicity varies among both primary and secondary pollutants. In fact, many secondary pollutants (which form through chemical reactions in the atmosphere) like ozone, peroxyacetyl nitrate (PAN), and photochemical smog can be more harmful than some primary pollutants. The toxicity depends on the specific pollutant, not whether it's primary or secondary.