Acid Rain

acid rain or acid deposition, form of precipitation (rain, snow, sleet, or hail) containing high levels of sulfuric or nitric acids (pH below 5.5–5.6). Produced when sulfur dioxide and various nitrogen oxides combine with atmospheric moisture, acid rain can contaminate drinking water, damage vegetation and aquatic life, and erode buildings and monuments. Automobile exhausts and the burning of high-sulfur industrial fuels are thought to be the main causes, but natural sources, such as volcanic gases and forest fires, may also be significant. It has been an increasingly serious problem since the 1950s, particularly in the NE United States, Canada, and W Europe, especially Scandinavia.

Acid rain became a political issue in the 1980s, when Canada claimed that pollutants from the United States were contaminating its forests and waters. Since then regulations have been enacted in North America and Europe to curb sulfur dioxide emissions from power plants; these include the U.S. Clean Air Act (as reauthorized and expanded in 1990) and the Helsinki protocol (1985), in which 21 European nations promised to reduce emissions by specified amounts. To assess the effectiveness of reductions a comprehensive study, comparing data from lakes and rivers across N Europe and North America, was conducted by an international team of scientists in 1999. The results they reported were mixed: while sulfates (the main acidifying water pollutant from acid rain) were lower, only some areas showed a decrease in overall acidity. It remained to be determined whether more time or a greater reduction in sulfur emissions was needed to reduce freshwater acidity in all areas. See air pollution; forest; pollution.

The Columbia Encyclopedia, 6th ed. Copyright© 2018, The Columbia University Press.

Acid Rain: Selected full-text books and articles

Aquatic Pollution: An Introductory Text By Edward A. Laws Wiley, 2000 (3rd edition)
Measuring the Benefits of Clean Air and Water By Allen V. Kneese Resources for the Future, 1984
Librarian's tip: "Acid Rain" begins on p. 111
Winds of Change: Reducing Transboundary Air Pollutants By Reuther, Christopher G Environmental Health Perspectives, Vol. 108, No. 4, April 2000
Peer-reviewed publications on Questia are publications containing articles which were subject to evaluation for accuracy and substance by professional peers of the article's author(s).
Game Theory and the Environment By Nick Hanley; Henk Folmer Edward Elgar, 1998
Librarian's tip: Chap. 5 "Acid Rain and International Environmental Aid: Transboundary Air Pollution between Finland, Russia, and Estonia"
International Environmental Cooperation: Politics and Diplomacy in Pacific Asia By Paul G. Harris University Press of Colorado, 2002
Librarian's tip: Chap. 10 "Problems of Environmental Cooperation in Northeast Asia: the Case of Acid Rain"
Acid Rain and the Adirondacks: A Legislative History By Melewski, Bernard C Albany Law Review, Vol. 66, No. 1, Fall 2002
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