Acid rain: Causes, Consequences, and Recovery in Terrestrial, Aquatic, and Human Systems

Abstract

Acid rain, or acid deposition, was determined to be a widespread environmental problem in the late 1960s and early 1970s in eastern North America and northwestern Europe. Acid deposition is largely attributed to the burning of fossil fuels, which in turn releases the acid deposition precursors, sulfur dioxide (SO2), mainly from power plants, and nitrogen oxides (NOx), mainly from vehicles. Early signs of environmental damage from acid deposition include the loss of fish populations in remote lakes and streams, and the die back of forests in Europe and eastern North America. Scientific evidence and public outcry in these regions led to legislation to reduce emissions of SO2, and then NOx, which resulted in dramatic declines in acid deposition and other related pollutants (e.g., particulates), and in many areas an improvement in ecosystem and human health. Some areas have only seen minor improvements due to long-term loss of acid neutralizing capacity in soils of acid sensitive landscapes, brought about by decades of acid deposition. SO2 and NOx emissions are increasing in parts of Asia, where the potential for future problems related to acid deposition still exists.