Predicted fate and transport of mercury emitted from utility boilers in the local atmosphere

In 1990, it was estimated that electric utility boilers accounted for approximately 21% of anthropogenic mercury emitted to the atmosphere in the USA. To characterize the electric utility industry, a series of model plants were developed. Using a modified version of the COMPDEP air model, the fate of the mercury emissions from the model plant developed to represent large coal-burning boilers was predicted. Estimated annual air concentrations at a hypothetical site 2.5 km downwind from the model plant were 0.001 ng/m² and the estimated annual mercury deposition rate was less than 10 ug/m²/yr. Of the mercury emitted from this model plant, less than 5% percent is predicted to deposit within 50 km of the emission source. The mercury remaining in the atmosphere is thought to become part of a regional and eventually global mass of atmospheric mercury