| Summary: | We have developed two effective aerosol dynamical models MULTIMONO and MONO32. The models take into account gas-phase chemistry and aerosol dynamics and includes the following processes: (1) emissions of gases and particles; (2) chemical reactions in the gas phase; (3) dry deposition of gases and particles; (4) homogeneous binary H2SO4-H2O or ternary H2SO4-H2O-NH3 nucleation; (5) multicomponent condensation of H2SO4, H2O, HNO3, NH3 and some organic vapour X onto particles; and (6) inter- and intramode coagulation of particles. The particles can be classified into four different size modes which are monodisperse (all particles in a mode possess the same size and composition). In these models the different aerosol properties, such as the particle number concentration, the particle diameter, the mass and composition of the whole distribution, and the mass of particulate matter smaller than 2.5 µm (PM2.5) and smaller than 10 µm (PM10) can be studied. Particles can include soluble material such as sulphate, nitrate, ammonium, and sodium chloride, as well as insoluble material such as organic carbon, elemental carbon, and mineral dust. We have chosen five different particle classes for each size mode (MULTIMONO), or assumed internally-mixed particles (MONO32). The developed models have been compared with a more detailed sectional model AEROFOR2. The comparison shows that the developed models are physically sound. The performed model runs show that the composition of aerosol particles depends mainly on emissions and condensation. Coagulation seems to be of minor importance. The state of mixing can be studied effectively using MULTIMONO or MONO32. E.g. the degree of internal mixing depends on the condensation rate and condensation time. The developed models can be used as sub-models in one-dimensional boundary layer models and three-dimensional Eulerian models.
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