Scientists from around the globe have come to a conclusion, on the basis of environmental evidence, that acid rain is now a serious problem in the industrialized regions of the world. Acid rain impacts on lakes and vegetation. Many lakes are extremely sensitive to acid rain because they are unable to neutralize it. Such lakes are either enclosed systems, that have no way of flushing out the acids, or lakes that cover relatively inert bedrock which does not react chemically to neutralize the acids. This affects the lake by making it unable to support fish. Forests are affected when acid rain falls on foliage or by changes in soil chemistry as a result of acid deposition. 

Acid rain is composed of antecedents that come mainly from the fossil fuels that humans used. The most common of these fossil fuel by-products are sulfur and nitrogen compounds. They are produced by electric power generation, industrial processes, cars, trucks, and space heaters. Aside from these man-made causes, natural occurrences like forest fires, organic decay, and lightning do generate some sulfur and nitrogen compounds. As soon as these compounds enter our atmosphere, photochemical reactions (sunlight) and chemical processes occur to make nitric and sulfuric acids in clouds.

There are both direct and indirect effects of acid rain on humans and various materials and structures. The acidic particles and those which form air pollution, pose a health problem in polluted environments, especially affecting the lungs. Also, acid rain could increase heavy metals in some fish which would impact human heath. Acid rain is also responsible for surface erosion, chemical alteration processes (e.g. corrosion and discoloration), and physical alteration processes (e.g. cracking and pitting).

Largely populated areas are not the only places that acid rain problems have been in effect. These problems are the results of human-produced nitrogen compounds, that are created miles away from the problem areas, and from natural hydrocarbons emitted by the vegetation. All this is extremely dangerous to the health and survival of certain crops that are taken for granted by our nation, as we think that they will always survive.

Another major problem with acid rain is that, although it is mainly in the northeastern United States and western Europe, scientists have noted that winds are gradually pushing the rain clouds over to other parts of the world that are considered safe right now, and are not prepared for a large case of acid rain. This has been noted by historians, who are able to see that many historical buildings such as the Colosseum in Rome, and certain cathedrals in Europe have been effected by acid rain. Much corrosion and deterioration has occurred from these waves of acid rain.

Scientists use the pH factor to determine what rain is acidic. The average normal rain ranges anywhere from 5.8 to 7. It has been determined that if the pH level of rain falls to 5.5 or lower, then it is acid rain. This is a very serious situation to reach, and what makes it worse is that many of the average rainfalls in the eastern United States and Western Europe range from a low 4.5 to 4.0.

Gould, Roy. Going Sour: Science and Politics of Acid Rain. Basel: Birkhauser, 1985.

Howard, Ross and Michael Perley. Acid Rain. New York: McGraw Hill, 1980.

Pringle, Laurence. Rain of Troubles: the Science and Politics of Acid Rain. New York: Macmillan Publishing Company, 1988.