Acid rain
From Encyclopædia
Acid rain is a common term for pollution caused when
sulfur and
nitrogen dioxides combine with atmospheric moisture to produce a rain, snow, or hail of sulfuric and
nitric acids. Such pollution may also be suspended in a fog, or the pollutants may be deposited in dry form. Environmental damage from acid rain has been reported in northern
Europe and North
America. High levels of acid rain have also been detected in other areas of the
world, such as above the tropical rain forest of
Africa. Acid rain has destroyed
plant and animal life in lakes, damaged forests and crops, endangered marine life in coastal waters, eroded structures, and contaminated drinking water.Research has shown that although some of the damage attributed to acid rain is a result of natural causes,
sulfur dioxide from oil and coal
combustion and
nitrogen oxides produced from automobile
engines have greatly intensified the acid rain problem. Winds can carry the pollutants thousands of kilometers away from their source. The British government has recognized that
sulfur emissions from power
plants in the United Kingdom are contributing to acid
deposition in Scandinavia. Canadian emissions contribute substantially to acid rain in the northeastern
United States, for example, and much of the
sulfur falling in eastern Canada is believed to originate in the
United States. In 1986 the U.S. National
academy of
sciences acknowledged that acid rain from U.S. sources had become a serious problem in the eastern
United States and Canada. Although the Canadian government has agreed to reduce
sulfur dioxide emissions, the
United States has not placed limitations on its
sulfur emissions that may drift into Canada.Scientists agree that acid rain is harmful, but reports concerning its severity conflict. A U.S. government report issued in September 1987 minimized the environmental damage caused by acid rain and concluded that the acid-rain problem is not increasing. A 1988 survey conducted by the Environmental Protection Agency, however, indicated that streams in the eastern
United States were more acidic than was previously believed. In 1990 the National Acid Precipitation
assessment Program (NAPAP), created by Congress in 1980, issued a report on the results of its study. The report indicated that acidic waters also occur in the southern and midwestern
United States but downplayed acid-rain damage to forests.Many scientists urge that measures to
Control acid rain begin immediately. The most direct action would be to cut off pollution at the source. Regulations require that new coal-burning
plants must install expensive scrubbers in their smokestacks to remove most of the dioxides (see
POLLUTION CONTROL). Other possible measures include burning only low-
sulfur oil or coal, or removing the
sulfur from coal with high
sulfur content. The 1990 revision of the Clean Air Act focuses on reducing urban smog, acid rain, and emissions. The costs of such measures are considerable, however, and who should pay these costs continues to arouse controversy.
bibliography: Bubenick, D. V., Acid Rain Information Book, 2d ed., (1984); Elliott, T. C., and Schwieger, R. G., eds., The Acid Rain Sourcebook (1984); Howard, Ross, and Perley,
Michael, Acid Rain (1982); Johnson, A. H., "Acid
deposition," Environment, May 1986; Martin, H. C., ed., Acid Precipitation (1987); McCormick, J., Acid Rain (1986); Mohnen, V. A., "The Challenge of Acid Rain," Scientific American, August 1988; Ostmann, Robert, Jr., Acid Rain: A Plague upon the Waters (1982); Park, C. C., Acid Rain (1988);
Rhodes, S. L., and Middleton, P., "The Complex Challenge of Controlling Acid Rain," Environment, May 1983; Schmandt, Jurgen, ed., Acid Rain and Friendly Neighbors, rev. ed. (1989); White, J. C., Acid Rain (1987); Yanarella, E., and Ihara, R. H., eds., The Acid Rain Debate (1985).
