A regional look at acid rain



New, detailed atmospheric computer models are beginning to reveal regional information about acid deposition in eastern North America and elsewhere, allowing scientists to look for the first time at the origin, transport, and deposition of acid rain and its dry equivalents on both a global and local scale. Interpretations of the simulations are expected to play a central role in future national policies on the human causes of the destructive fall-out.

One new model developed by Hiram Levy II and Walter Moxim at the Geophysical Fluid Dynamics Laboratory in Princeton, N J., yields results indicating that over the course of a year, nitrogen-based compounds, which make up one half of the acid material that falls from the sky, are deposited for the most part near the industrialized population centers where they originate, particularly in the northeast United States (see figure). Another model, even more detailed and complex, is being developed for the Environmental Protection Agency (EPA) to predict over shorter periods of time the transport and deposition of a variety of chemicals that cause acid precipitation.