Posted: March 24th, 2017

Which of the following describes changes in the 5 criteria air pollution in the U.S. since the enactment of the Clean Air Act?

Which of the following describes changes in the 5 criteria air pollution in the U.S. since the enactment of the Clean Air Act?

A) emissions have decreased but ambient air quality remains the same.

B) they have decreased substantially.

C) they are about the same.

D) they have increased because of economic growth and more automo- biles.

E) they have become steadily worse.