The oxidation of sulfur dioxide to sulfate aerosols in the plume of a coal-fired power plant

Abstract

Instrumented aircraft have been used to determine the rate of oxidation of sulfur dioxide to sulfate aerosols within the dispersing plume of a coal-fired power plant. Measurements have been made in the stack and from 10 to 105 km downwind of a 2600-MW power plant. Sampling experiments were conducted during the winter of 1975-1976 and in the fall of 1976. Average temperatures and relative humidities varied from -5 to 17°C and 22 to 71% respectively. Data were also collected on sulfate production at night. An average of 1.1% and a maximum of 4.3% of the plume sulfur was in the form of sulfate. Most of the atmospheric oxidation that was observed appeared to occur in the immediate vicinity of the power plant. The average oxidation rate, beyond 10km, was found to be 0.2% h-1. Analyses of individual particles showed that the sulfur found in plume particles is usually associated with submicron fly ash particles. © 1978.