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Micro-scale processes of dust distribution in the city of Tbilisi with very complex topography are modeled using a 3D regional model of atmospheric processes and numerical integration of the transport-diffusion equation of the impurity. The Terrain-following coordinate system is used to take into account the influence of a very complex relief on the process of atmospheric pollution. Modeling is carried out using horizontal grid steps of 300 m and 400 m along latitude and longitude, respectively. Cases of the stationary background eastern light air are considered. In the model, motor transport is considered as a nonstationary source of pollution from which dust is emitted into the atmosphere. Modeling of dust micro-scale diffusion process showed that the city air pollution depends on the spatial distribution of the main sources of city pollution, i.e. on vehicle traffic intensity, as well as on the spa

The distribution of PM2.5 in the atmosphere of the city of Rustavi and its environs was studied under eastern background light air, gentle and fresh breeze. It has been established that the maximum concentrations of PM2.5 in the atmosphere of Rustavi are almost always higher than the corresponding maximum allowable concentrations. The trend of hourly changes in concentrations showed that during the day the concentration of microparticles reaches its maximum in the various period of the day. Numerical modeling of the local distribution of microparticles carried out in the city of Rustavi during background easterly light air, gentle and fresh breeze showed us that the change in the daily regime of relief and temperature with eastern light air in Rustavi for 12 hours leads to a complex and significant change in the wind speed directed to land. It forms on the territory of Kvemo Kartli the opposite current of the background wind, which corresponds to the horizontal circular wind circulation. The value of circulation gradually decreases with increasing height and in the boundary layer of the atmosphere (600 m above the earth's surface) has the form of a wave disturbance. the picture obtained with an average background east wind is qualitatively similar to the field obtained with a background light air, and with a fresh breeze, in contrast to the case of a light air and gentle breeze, the pollution zone covers most of the simulation zone.

Dust distribution of the industrial town of Zestafoni located in the complex territory of Georgia in case of basic meteorological situations and stationary pollution sources is studied with the use of regional model of atmospheric process development in the Caucasus and non-stationary threedimensional equation of transfer-diffusion of passive admixtures. Distribution patterns of dust dissipated in the atmosphere are obtained at different levels from the surface. It is shown that dust dissipated from cities in the atmosphere is basically concentrated in the boundary layer. Maximum values of dust concentration are obtained in the lower 100 m of surface air layer. Spatial dust distribution region increases and concentration decreases along with height increase. An influence of local orography on the pollution cloud is investigated. During a background western light air Likhi and Racha ridges impede dust transfer to the east and cause dust cloud deformation. Dust spreads along the valleys of Kvirila and Chkherimela rivers located between the ridges. In the case of gentle and fresh breezes the impact of local orography on the dust dispersion process is insignificant. Dust is basically transferred in the direction of background flows. The zone of influence of industrial town dust on the environmental pollution is determined. A width of this area varies from 5 to 20 km in dependence of the background wind velocity. Kinematics of dust propagation is studied. It is determined that in 2-100 m layer of atmosphere the process of turbulent diffusion takes precedence in the process of dust spreading. From 100 m to 1 km the processes of diffusive and advective transfers are identical, while above 1 km the preference is given to advective transfer.