Chay and Greenstone (2003)estimated the Effect of the Clean Air

Multiple Choice

Chay and Greenstone (2003) estimated the effect of the Clean Air Act of 1970 by comparing the health outcomes of people in attainment areas with those of people in nonattainment areas both before and after the law was passed.What did they find?

A) Reduced emissions led to a decrease in infant mortality.
B) Reduced emissions did not affect infant mortality.
C) The Clean Air Act of 1970 did not affect emissions in any states.
D) The Clean Air Act of 1970 affected different regions of the country in the same way.