A Brief History Acid rain was first observed in the mid 19th century, when some people noticed that forests located downwind of large industrial areas showed signs of deterioration. Smith observed that acidic precipitation could damage plants and materials. Acid rain was not considered a serious environmental problem until the 1970s. During that decade, scientists observed the increase in acidity of some lakes and streams. At the same time, research into long range transport of atmospheric pollutants such as sulfur dioxide, indicated a possible link to distant sources of pollution.
Many power plants use coal with a relatively high concentration of sulfur as fuel.
Scientists realized that sulfur dioxide emitted from many of these plants could be transported to the Northeast. When we began to see acid rain as a regional, rather than a local, problem, the federal government had to become involved. In 1980, the U.S. Congress passed an Acid Deposition Act. It enlarged a network of monitoring sites to determine how acidic the precipitation actually was, and to determine long term trends, and established a network for dry deposition. It looked at the effects of acid rain and funded research on the effects of acid precipitation on freshwater and terrestrial ecosystems, historical buildings, monuments, and building materials.