- Analysis of heavy pollution process in Xuzhou in winter based on multi-source comprehensive observation
- 基金项目：国家自然科学(41771435)；国家重点研发计划(2017YFB0503605)Supported by the National Natural Science Foundation of China (No. 41771435) and the National Key Research and Development Program of China (No. 2017YFB0503605)；徐州市重点研发计划(社会发展KC20057)
- Abstract：After years of air pollution control, the concentration of a variety of air pollutants in China has shown a significant downward trend. However, it will still lead to the occurrence of heavy pollution events under unfavorable meteorological conditions. Understanding the causes and mechanisms of the occurrence and development of such occasional heavy pollution events will be helpful for the prevention and control of air pollution in the next step. In this study, a heavy pollution process in Xuzhou in mid-December 2020 was taken as an example. Comprehensive observation and analysis were carried out by means of ground station observation, Lidar, model simulation, particle component observation and source apportionment, and backward trajectory tracing. The results showed that the main sources of particulate matter in the pollution process were from secondary ions, coal burning, biomass combustion, motor vehicles, and dust, of which secondary ions accounted for 37.9%. Sulfur oxidation rate and nitrogen oxidation rate increased by 176% and 82%, respectively, during pollution period. During the pollution period, SO42-, mainly from coal burning sources, increased significantly from 5.51μg/m3 to 16.3μg/m3, with an increase of 196%. The tracer K+ of biomass combustion increased from 0.37μg/m3 to 0.83μg/m3 with an increase of 123%. In the early stage of pollution, the main external unfavorable meteorological factors, such as local high humidity and static stability, promoted the generation of local pollutants. In the middle stage of pollution, the increase of pollutant transport in Shandong and Anhui province was more obvious, and the regional transport contribution increased to 74.4%. The study shows the complexity of the pollution process and the uncertainty brought by the change of meteorological and emission factors, which provides a basis for understanding the pollution mechanism and improving regional joint prevention and control.