Acid rain is a term that refers to not just rain but also other forms of precipitation such as snow, hail, sleet, and fog that has a higher acidity than normal. Acid rain is caused by the burning of ...

In the 1970s, acid rain was one of the most serious environmental threats in North America and Europe. The air was so laden with pollution from coal power plants and cars at the time that it turned ...

Depleted ecosystems, dwindling forests, contaminated drinking water and toxic soil. All due to what Canada's Environment Minister John Roberts called in 1980 "the most serious environmental threat to ...

Hoof it through the national parks of the western United States—Joshua Tree, the Grand Canyon, Bryce Canyon—and breathe deep the pristine air. These are unspoiled lands, collectively a great American ...