You are here:
LABORATORY MEASUREMENT OF SULFUR DIOXIDE DEPOSITION VELOCITIES
Citation:
Judeikis, H. AND T. Stewart. LABORATORY MEASUREMENT OF SULFUR DIOXIDE DEPOSITION VELOCITIES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/3-77/027.
Description:
Measurements of sulfur dioxide deposition velocities have been carried out in the laboratory with the use of a cylindrical flow reaction. Analysis of data from these experiments was performed with models that specifically account for diffusive transport in the system. Consequently, the resulting deposition velocities were independent of diffusion processes and represented the maximum removal rates that would be encountered in the environment under turbulent atmospheric conditions. The measured values ranged from 0.04 cm/sec for asphalt to 2.5 cm/sec for cement, and were independent of sulfur dioxide and oxygen concentrations as well as relative humidity and total pressure. Prolonged exposure to sulfur dioxide eventually destroyed the ability of the various solids to remove this species. Overall capacities increased significantly at moderate relative humidities, yielding values of 0.4 to 2.8 grams of sulfur dioxide per square meter of solid in moist systems. Several experiments indicated that the reactivity of a solid subjected to prolonged sulfur dioxide exposures could be restored by washing the surface with distilled water or exposing the spent solid to ammonia. Some implications of these findings relative to the environment are discussed.