Since the Clean Air Act of 1970, emissions of most pollutants have fallen off substantially, with _____ showing the greatest reduction.
A)sulfur dioxide
B)methane
C)lead
D)carbon dioxide
E)carbon monoxide

Question

Quizplus · Accepted Answer

Lead emissions have shown the greatest reduction since the Clean Air Act of 1970, largely due to the phase-out of leaded gasoline and tighter emission controls.

Since the Clean Air Act of 1970, Emissions of Most