Which one of the following statements best describes the results of the Clean Air Act in the United States?

Which one of the following statements best describes the results of the Clean Air Act in the United States?

a) It has been successful at reducing levels of both criteria and toxic pollutants.

b) It has been unsuccessful at reducing levels of both criteria and toxic pollutants.

c) It has been successful in reducing levels of criteria pollutants, but levels of toxic pollutants have increased.

d) It has been successful in reducing levels of toxic pollutants, but levels of criteria pollutants have increased.

e) It is too early to judge whether the Clean Air Act has reduced pollution levels.

Answer: a) It has been successful at reducing levels of both criteria and toxic pollutants.

The essential base to minimize aeriform emissions in the United States of America has been created with the help of the Clean Air Act which covers both criteria air pollutants as well as toxic air pollutants. Since its establishment, the act has helped lead the measures within the objective average parameters, which are dangerous for human health and the environment, such as particulate matter, ozone, carbon monoxide, and lead. Besides, new source reviews and prevention of significant deterioration have also helped in regulating and controlling the quantity of hazardous air pollutants like benzene and mercury that are dangerous to public health. To this effect, the Level II emission standards, technology, and enforcement systems that the Clean Air Act endorses have achieved the reduction of both classes of pollutants, and the qualitative enhancement of fresh air freely available in the United States.