Mathematical modelling of the interaction of gas species and aerosols in atmospheric dispersive systems

We consider the mathematical model of a multicomponent pollutant transport, taking into account photochemical transformation and aerosol formation in the troposphere of the Northern Hemisphere and kinetic processes of nucleation, condensation, and coagulation. The size distribution of aerosol particles is resolved for 25 discrete intervals starting from 10(-5) mu m, with separation between intervals doubled. In the model we consider the oxidation processes of gaseous sulphur dioxide by a series of photochemical reactions with the formation of sulphuric acid vapour. At certain levels this leads to supersaturation of H2SO4-H2O with the subsequent precipitation of the water solution of sulphuric acid on the surfaces of condensation nuclei. The drops can increase in size or evaporate depending on the area and physical environment. If they evaporate, their interiors are released as solid nuclei. We consider the main principles of the construction of mathematical models and the algorithms of their numerical implementation. We give the results of numerical experiments on modelling the transformation of sulphuric acid vapour and the formation of condensation trails in the troposphere of the Northern Hemisphere.