Areas of Probable Air Pollution in Mountains and Valleys

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Many cities of the world are located in river valleys or are associated with mountains. The article presents the characteristic landscape positions of many cities in the world. Among them is very important to study the wind regime, which is located in the conditions of the basin. In these cities, general pollution and deterioration of the microclimatic regime of the atmosphere are observed during periods of windless weather, and especially during inversions. It occurs either due to the gradual accumulation of harmful impurities of road transport under adverse meteorological conditions. The contribution of vehicles to the total air pollution is up to 80%. Currently, their composition of vehicle exhaust gases contains more than 200 different substances. With 95 … 99% of emissions t represent an aerosol of complex composition, depending on the engine operating condition and the composition of the mixture. The composition of the atmosphere of cities should meet the established standards for the content of the main components of air and harmful impurities (dust, gases), taking into account existing state standards. Biomedical requirements for the composition of air in cities are determined by the maximum permissible concentrations (MAC). However, the content of toxic substances in the air at the level of the MPC cannot be considered as the optimal composition of the air environment. In cities located in the depressions, deterioration of air exchange conditions is observed, which is associated both with a drop in wind flow activity and a decrease in the intensity of solar insolation per unit area of exposed surfaces of the slopes. In the work to improve the wind mode, the base for establishing the main stages for regulation is set to be direct; recycling; and combined i-recirculation direct-flow, as well as direct-flow-recirculation schemes of natural ventilation. The formulas for determining the criterion for evaluating the effectiveness of ventilation are given. We used computer modeling technologies that significantly simplify the analysis of the wind regime and reduce the time spent on research, the purpose of which was to compare the results of experiments in a wind tunnel with the data of virtual studies of the wind flow around natural wind patterns in a wind tunnel with the use of SolidWorks 2015, with the addition of Flow Simulation.