Source Apportionment Of Fine Particulate Matter PM_2.5 In Tianshui Based On The WRF-CMAQ-ISAM Model

Atmospheric fine particulate matter PM_2.5pollution is one of the main atmospheric environmental pollution problems faced by most cities in my country,and it has an important impact on human health,atmospheric chemical reactions,and global climate change.The most polluted weather accounts for the highest proportion,among which the primary pollutants are PM₁₀and PM_2.5.Therefore,the PM_2.5pollution problem in Tianshui City still needs to be studied accordingly.In this study,the CMAQ-ISAM source analysis model was used to simulate the PM_2.5spatial distribution and concentration contribution levels of different emission sources in the study period.The transportation route and potential source areas of pollutants in the city were further analyzed.Finally,based on the source analysis results of this study,suggestions for reducing and controlling PM_2.5of fine particulate matter in Tianshui City were put forward.The conclusions of this study are as follows:（1）Analysis of all-source PM_2.5simulation results.In January,the two districts of Tianshui City,Gangu,and Wushan counties had belt-shaped high-value areas of pollution,and there were spot-shaped high-value areas in the urban area of Qin’an County,while the southeastern part of Tianshui City was always in the extremely low-value area of PM_2.5;the PM_2.5concentration in July Compared with January,the PM_2.5concentration distribution area is relatively stable during the simulation period,and the range of the high concentration area shrinks.（2）Analysis of PM_2.5source analysis results.The main contribution sources of the cultural center site are boundary and extra-territorial transportation,construction dust,road dust,and fossil combustion.Contribution source areas are boundary and extra-regional transportation,the periphery of Tianshui City,road dust,fossil combustion and other sources.The contribution of construction dust sources is greatly reduced,while the contribution of boundary and extra-regional transportation and Tianshui peripheral sources is much higher than the contribution to the urban area;In July,the contribution ratio of boundary fields and extra-regional transport sources in the region was significantly reduced.（3）Analysis of PM_2.5transport paths and potential sources.Tianshui City is most affected by the southeastern and southern transportation routes,followed by the northern route.The main wind direction in Tianshui City is basically the same as the transportation direction of major pollutants,and the transportation is concentrated in the southern and northern parts of the site.The results of potential source analysis show that the potential source areas that have the greatest impact on Tianshui City are the linear source areas at the junction of Gansu and Ningxia,and the point source areas distributed in Baoji,Pingliang,and Guangyuan.The contribution of the weighted concentration value is 50～100μg/m~3,and the contribution in July is10～15μg/m~3.（4）Suggestions for PM_2.5emission reduction and control of fine particulate matter.Based on the results of this source analysis and research,aiming at the main emission characteristics of PM_2.5pollution in Tianshui City,the following suggestions for emission reduction and control are put forward:strengthen the management and control of fossil combustion sources in Tianshui City in winter;improve comprehensive control measures for road dust and construction dust;Rationally distribute industrial enterprises,vigorously control industrial emissions;pay attention to the influence of external sources,and establish regional collaborative management.