Acid Rain 8

Acid Rain is a type of air pollution, which is formed when oxides of sulfur and nitrogen combine with atmospheric moisture to yield sulfuric and nitric acids, which may then be carried long distances from a source before they are deposited by rain. This pollution may also take the form of snow, fog, or a dry form of precipitation. Acid rain is currently a subject of great controversy because of widespread environmental damage, for which it has been blamed, including eroding structures, injuring crops and forests, and threatening or depleting life in freshwater lakes. The problem of acid rain originated during the Industrial Revolution, and has been growing ever since. The severity of its effects has long been recognized in local settings, exemplified by the spells of acid smog in heavily industrialized areas. The widespread destructiveness of acid rain, however, has become evident only in recent decades. One large area that has been studied extensively is northern Europe. In 1984, for example, environmental reports indicated that almost half the trees in Germany's Black Forest had been damaged by acid rain. This form of pollution has also particularly affected the northeastern United States and eastern Canada.

Industrial emissions have been blamed as the major cause of acid rain. Because the chemical reactions involved in the production of acid rain in the atmosphere are complex and as yet little understood, industries have tended to challenge such assessments and to stress the need for further studies; and because of the cost of pollution reduction, governments have tended to support this attitude. Studies released by the U.S. government in the early 1980s, however, strongly implicated industries as the main source of acid rain in the eastern United States and Canada. In 1988, as part of the United Nations-sponsored long-range Transboundary Air Pollution Agreement, the United States and 24 other nations ratified a protocol freezing the rate of nitrogen