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REGIONAL PARTICULATE MODEL - 1. MODEL DESCRIPTION AND PRELIMINARY RESULTS
Citation:
Binkowski, F.S. AND U. Shankar. REGIONAL PARTICULATE MODEL - 1. MODEL DESCRIPTION AND PRELIMINARY RESULTS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-96/028, 1995.
Description:
The gas-phase chemistry and transport mechanisms of the Regional Acid Deposition Model have been modified to create the Regional Particulate Model, a three-dimensional Eulerian model that simulates the chemistry, transport, and dynamics of sulfuric acid aerosol resulting from primary missions and the San-phase oxidation of sulfur dioxide. he new model uses a bimodal lognormal distribution to represent particles in the sub-micrometer size range. n addition to including the horizontal and vertical advection and vertical diffusion of the aerosol number concentration and sulfate mass concentration fields, the modal now explicitly treats tho response of the distribution parameters to particle coagulation within and between the modes, condensation of sulfate vapor onto existing particles, and the evaporation and condensation of ambient water vapor in the presence of ammonia. n engineering version of the model that has a simplified chemistry for sulfur has been used to study how the degree of sulfuric acid neutralization by ambient ammonia affects the total aerosol volume, surface area, and number concentrations over eastern North America. reliminary results for three representative locations - rural, near-source, and nominal downwind-of-source show that the effect is greatest for the rural and smallest for the near-source regions, which corresponds with the largest and smallest values, respectively, of ammonium-to-sulfate molar ratios. he results indicate that the model could provide a tool for investigating the effects of various pollution control strategies, as well as now or alternative formulations of important aerosol processes.