台风持续影响下中山市大气O₃污染过程分析

The three-dimensional air quality model (Model-3/CMAQ) coupled with the Integrated Process Rate (IPR) analysis tool was applied to analyze the ozone pollution process which lasted for six days in Zhongshan under the continuous influence of the four typhoons in the summer from July 22 to 31, 2017. The dominant physical and chemical processes of maximum 8-hour ozone were further investigated, and the contributions of different sources and sinks to ozone concentration were quantified by IPR. The results showed that due to the continuous impact of typhoons, the proportion of source contribution to ozone by chemical process was higher during the pollution period than that of non-pollution period, indicating more active photochemical reactions during the pollution period. Furthermore, under the impact of typhoons, the contribution of chemical process increased significantly when the air mass from high pollution emitted area was 2.4%~6.5% higher than that of low pollution emitted area. At last, horizontal transport took the largest contribution to ozone source process, with the scale of 56.6%~92.6%. Therefore, in addition to the strict local emission control, the regional joint prevention which was combined with the path analysis of regional air mass, precise identification of high pollution areas, and the coordinated emission reduction measures in the upwind areas, could be more effective to improve the air quality.