CSAPR protects the health of millions of Americans by helping states reduce air pollution and attain clean air standards. This rule requires states to significantly improve air quality by reducing power plant emissions that contribute to ozone and/or fine particle pollution in other states.

In 2009, EPA determined that greenhouse gas pollution threatens Americans' health and welfare by leading to long lasting changes in our climate that can have a range of negative effects on human health and the environment. Carbon dioxide (CO₂) is the primary greenhouse gas pollutant, accounting for nearly three-quarters of global greenhouse gas emissions and 84% of U.S. greenhouse gas emissions.  On August 3, 2015 EPA finalized the Clean Power Plan Rule to cut carbon pollution from existing power plants.

The Acid Rain Program, established under Title IV of the 1990 Clean Air Act (CAA) Amendments requires major emission reductions of sulfur dioxide (SO2) and nitrogen oxides (NOx), the primary precursors of acid rain, from the power sector.

This site explains the chemical element mercury, how it gets into the environment, how we are exposed to mercury, and what health effects and ecological exposure to mercury means.