Wetfall chemistry studies around a large coal‐fired power plant in the southeastern United States

Abstract

A wetfall chemistry study was conducted within a 15‐km radius of a large coal‐fired power plant in the southeastern United States. The study was conducted during the winter of 1981 and included event precipitation sampling on a dense network of 31 stations, selected air chemistry monitoring at two sites, and extensive meteorological measurements. The precipitation samples were analyzed for all major inorganic ionic species, including dissolved sulfur dioxide. The meteorological network included a preexisting network of 49 recording rain gages and four surface windsets, the power plant's fully equipped meteorological station, and a bistatic acoustic sounder. This paper presents the results from five of the sampled storms. Plume washout is evident in most target area samples, and sulfur, hydrogen ion, and chloride ion were found to be the predominant plume‐related species. Concentrations in the affected regions exceeded the background levels by up to 100% in the case of sulfur and of hydrogen ion, and by up to 145% in the case of chloride ion. Two of the storms were characterized by excess dissolved SO2 amounts in the target samples; for these storms, scavenging model simulations of dissolved SO2 concentrations indicated that deposition of sulfur by SO2 scavenging within 12 km was probably less than 2% of the total emitted. Based on the measured Cl− in rainwater, an estimate of the source strength (coal Cl content) using conventional gas scavenging theory appears reasonable.