Modeling of Pollutants in the Atmosphere Based on Photochemical Reactions

Abstract

<p>This article is devoted to the problem of the propagation of harmful pollutants in the atmosphere from point sources taking into account photochemical transformations. A complete list of typical atmospheric pollutants of the industrial city was determined. The fifteen most common types of harmful substances such as NO<sub>2</sub> (nitrogen dioxide), H<sub>2</sub>SO<sub>4</sub> (sulfuric acid) to examine the transformation of impurities were selected. A scheme for the conversion of pollutants by chemical reactions was created. The transfer process and the transformation of substances were described by a system of differential equations. The resulting differential equations are constructed on the basis of stoichiometric formulas and the constant of reaction rate in accordance with the law of mass conservation. To account for the influence of anthropogenic heat sources and heterogeneity of the underlying surface on the propagation of harmful substances taking into photochemical reactions, a model of atmospheric boundary layer and the transport equation and transformation of pollutants by the example of the city of Ust-Kamenogorsk was considered. The schemes of stable and convergent difference for the equations of the atmospheric boundary layer and transport and transformation of admixture of harmful substances were designed. A software package for numerical simulation of air pollution taking into account photochemical transformations and corresponding visualization of scenarios was developed. The software package allows simulating the spread of pollutants under different weather conditions. The results of the daily monitoring of distribution and dynamics of the formation of chemical substances were obtained. The results of numerical simulation of the propagation and transformation of harmful impurities on mesometeorological background processes taking into account the terrain and water surfaces were presented. The analysis of the propagation of the substance concentration taking into the transformation of harmful substances of components was carried out. The results show that the description of photochemical reactions in the mathematical model proposed in this paper allows identifying areas which are heavily contaminated with salts such as MgSO<sub>4</sub>, CaSO<sub>4</sub> and acids of H<sub>2</sub>SO<sub>4</sub> with a reasonable accuracy due to the sequantial chemical reactions taking place in the atmosphere.</p>

Determination of the Probability Factor of Particles Movement in a Gas-Dispersed Turbulent Flow

“…When wind speed is 3 m/s impurity is carried away faster, avoiding diffusion processes influence (Figure 2). (road network of cities) were taken from works [6][7][8], and Figure 4 provides the results of numerical calculation of the task (2), (5), (6), coincide with the result of the work [7,8].…”

“…Thus, if it is required, we can define amount of impurities that were brought out from computational region for self-purification with wind regimes and secondsolid boundary. (6) in this case the impurity neither flows in nor flows out. In the same way it is possible to get boundary conditions for other boundaries of the considered area.…”

Information system for monitoring of urban air pollution by heavy metals

“…During the implementation of the work, the system inverse modeling and data assimilation framework (IMDAF) was used [30]. The IMDAF system solves a hierarchy of increasingly complex mathematical modeling problems: direct problems, sensitivity assessment problems, inverse problems, and data assimilation problems.…”

“…In the Republic of Kazakhstan, research in this direction is actively conducted in the industrial city of Ust-Kamenogorsk by scientists of D. Serikbayev East Kazakhstan Technical university [27]- [30]. In the Commonwealth of Independent States according to the direction involved: Institute of computational mathematics and mathematical Geophysics Siberian Branch of Russian Academy of Sciences (SB RAS) (Novosibirsk, RF), Institute of numerical mathematics of Russian Academy of Sciences (Moscow, RF), Institute of computational technologies SB RAS, M. V. Lomonosov Moscow State University (RF).…”

Development of mathematical models of gas leakage and its propagation in atmospheric air at an emergency gas well gushing

“…There are many papers devoted to theoretical studies of atmospheric turbulence and spread of industrial releases. For example, turbulent exchange in an elevated inversion layer is studied in [16], influence of anomalous stratification on initial rise of pollution caused by releases from a technogenic source is considered in [17] and influence of wind speed variation with altitude on distribution of technogenic pollutants in the near-surface atmosphere layers is studied in [18]. However, physical patterns of release, transfer, and dispersion of natural gas in the event of emergency releases are characterized by a considerable complexity and differ significantly from classical releases, such as those from chimneys.…”