Development and application of a new air pollution modeling system—II. Aerosol module structure and design

摘要: Abstract The methods used for simulating aerosol physical and chemical processes in a new air pollution modeling system are discussed analyzed. Such include emissions, nucleation, coagulation, reversible chemistry, condensation, dissolution, evaporation, irreversible sedimentation, dry deposition, radiative scattering absorption by particles. A particle size bin structure that nearly eliminates numerical diffusion during growth but still treats transport realistically is discussed. In addition, coagulation shown to reduce the number volume concentration of particles less than 0.2 μm diameter both presence absence modest rates growth. However, when significant occurs, effect reduced. Further, while sulfate production due SO2 dissolution oxidation cloud drops confirmed be important, it here such aerosols small over time periods simulated urban models. Finally, light coefficient predictions, obtained applying Mie code stratified spheres, match data given scenario. Remaining module described.