Calculation of ground-level concentrations and mapping of pollutant dispersion fields

This article examines the impact of building materials manufacturing on public health and the environment. It is noted that the assessment processes were carried out on the basis of modern software and the analysis of the width of the atmospheric emissions of harmful substances emitted by enterprises. In addition, the use of normative documents, the accounting of the sources of emissions are recorded. And also, the rules for the field of dispersion of pollutants in the surface layer of the atmosphere are given.


Methods
To calculate the dispersion of pollutants into the atmosphere, in addition to the parameters of the emission sources, the following initial data are required: * climatic and meteorological characteristics and coefficients that determine the conditions for the dispersion of pollutants in the atmospheric air in the area of the enterprise location. * data on the coefficient that takes into account the sedimentation rate of impurities; * coefficient of relief.
Meteorological characteristics are taken according to the data of the nearest weather station to the enterprise. [2] The aim of the research is to reduce the excessive pollution of the atmosphere by pollutants and dust emitted from sources in industrial, construction and other manufacturing enterprises in industrialized areas. It is important to analyze and scientifically substantiate them in modern computer programs based on the state of the environment in which enterprises operate. Scientific novelty is the impact of industrial enterprises on the atmosphere and cases of excessive pollution studied in Samarkand region and in a particular region. In addition, the scope of impact of enterprises on the environment has been implemented on the basis of today's modern projects. [3,4] As part of this study, the laboratory of microclimate and environmental protection of Samarkand State Institute of Architecture and Construction analyzes pollutants in the atmosphere based on long-term data on water, soil and atmospheric air. For the first time, a comprehensive analysis of dust and other pollutants emitted into the environment by industrial and industrial enterprises is carried out. [5] The method of laboratory and computational analysis is used in the new and modern program "Ecologist". This method provides specific results for calculating the dispersion of pollutants in the atmospheric air.

Analyses and calculations
The area where the ABZ site is located has an agricultural and industrial orientation of management, where along with agricultural branches -cotton growing, there are enterprises of the construction industry. From the north, 70 m from the enterprise under consideration, there is a flour mill, from the sources of emissions, the flour mill will be 265 m. The wind rose is directed in such a way that the pollutants will be directed to the west. [6] Source-boiler room. The release occurs during the combustion of natural gas in the boiler room, where one boiler of the E-1/9 brand is installed. The annual gas consumption is 66.0 thousand m3 / year. The calculation of pollutants generated during gas combustion was carried out according to the methodology (Instructions for conducting an inventory of pollution sources and normalizing emissions of pollutants into the atmosphere for enterprises of the Republic of Uzbekistan. 3 January 2006, No. 1553).
The gross emission of nitrogen oxides released into the atmosphere is calculated by the formula: MNOx =0,001*B*Q H P *KNO2* (1-β), т/г (1) Β-fuel consumption, 66.0 thousand m3 / year. KNO2-a parameter that characterizes the amount of nitrogen oxides formed per 1 GJ of heat, kg/GJ (0.075 for plants with a capacity of 12.5 t/h.  It was determined that the harmful substances emitted from the asphalt concrete plant did not exceed the permissible limit based on the results of the analysis.
The calculation of the concentrations of pollutants in the atmospheric air was carried out according to the "Ecologist" program. The initial data was taken from the parameters of the emission sources. Meteorological characteristics and coefficients that determine the degree of dispersion of chemicals into the atmosphere.

Discussion
The calculation of the dispersion of pollutants is carried out outside the industrial site, in the fractions of the MPC (average-daily) for the atmospheric air of settlements. The map of the fields of pollutant dispersion in the atmospheric surface layer must contain the numbers of maximum concentrations in fractions MPC (average-daily). in the nodes of the computational grid and clearly marked boundary of the industrial site. [7] The environmental impact assessment of the bitumen storage facility of LLC "Samarkand Uzbekgazsuv Kurilish" in the Jambai district showed that the area of the object location is classified as a moderate pollution zone in terms of the degree of pollution of atmospheric air, soil and groundwater, and soil and vegetation cover. The activity of the facility is the reception, storage and heating of bitumen. The annual turnover of bitumen is 4,200 tons per year.
According to the calculated data, the following level of atmospheric air pollution was determined outside the industrial site of the enterprise: It should be noted that in this study for the first time in industrial enterprises of the area under consideration, the influence of harmful substances in the atmospheric air completed with new and modern projects using the method of laboratory analysis. Previously, the analysis and assessment of the impact of pollutants on the environment were carried out by the calculation and analytical method many times, and the method of laboratory analysis was carried out very rarely and the calculations were done according to the "Rainbow" program. The method of laboratory analysis in the new and modern project "Ecologist" shows the dispersion of pollutants very specifically. Differential experimental schemes showed a difference in the analysis calculations ( Table 2). The difference of the nitrogen dioxide analysis is 9%.