The U.S. Environmental Protection Agency ( is offering new tools on its Web site to help the public follow nationwide changes in sulfur dioxide (SO2) emissions from coal-fired power plants. Using interactive charts and Google Earth satellite maps, visitors can observe recent changes in SO2 emissions and other indicators at individual coal-fired power plants currently enlisted in the EPA’s Acid Rain Program.

The Acid Rain Program was established under the 1990 Clean Air Act Amendments requiring power plants to reduce emissions of SO2 and nitrogen oxides (NOx) — the primary causes of acid rain. According to the EPA, electric generating units subject to the market-based cap and trade SO2 program emitted 7.6 million tons of SO2 in 2008, well below the current annual emission cap of 9.5 million tons.

For more information on the EPA interactive emissions tracking tool, visit