Acid Rain

Acid emissions mainly come from the sulfur content in coal and oil. The sulfur element in fossil fuels converts to sulfur dioxide when burned. This gas can dissolve in water, producing sulfuric acid. This acid precipitates as rain, snow and mist. It can damage trees and hurts fish and wildlife when collected in lakes. It can also damage buildings, car finishes, and crops. Nitrogen released in fuel combustion can react and form acid rain as well.

For more information on acid rain, visit these EPA pages...
http://www.epa.gov/airmarkets/acidrain/index.html

or this Wisconsin DNR page...
http://dnr.wi.gov/org/aw/air/global/global.htm