One of the great environmental issues of the 1970s and 1980s was the problem of acid precipitation. Research studies suggested that rain, snow, and other forms of precipitation in certain parts of the world had become increasingly acidic over the preceding century. The southern parts of Scandinavia and England, the Northeastern United States, and Eastern Canada were four regions in which the phenomenon was particularly noticeable.

Evidence began to accumulate that the increasing level of acidity might be associated with environmental damage, such as the death of trees and aquatic life. Scientists began to ask how extensive this damage might be and what sources of acid precipitation could be identified.

If any single person could be credited with raising international awareness of this problem, it would probably be the Swedish agricultural scientist Svante Od...