沿海城市群氯化学对大气二次污染影响的数值模拟研究

城市地区大气污染物如NOx、VOCs等与OH自由基反应生成臭氧、二次气溶胶是导致大气二次污染的主要途径。然而，除OH·外，氯自由基(Cl·)亦在城市大气化学中扮演了重要角色，Cl·对城市大气氧化能力、臭氧、硝酸盐及SOA的生成均具有重要影响。已有外场观测显示，我国城市地区Cl2浓度较高，特别在沿海区域其来源更为复杂，氯在大气污染中的重要性已逐渐通过外场观测得到证实。然而，当前数值模式中的氯化学机制十分欠缺，有关氯前体物的源排放以及氯化学对二次污染影响的研究十分有限，严重制约了对沿海城市群大气复合污染机制的深入认知。为此，本研究拟以长三角城市群为案例，系统构建氯前体物排放源清单，发展适用于我国沿海城市群的氯化学机制并改进三维数值模型，系统探究氯化学对O3和硝酸盐、SOA的影响，并研究考虑氯化学在内的大气二次污染控制路径，以期为我国大气污染防治提供理论依据。

Secondary air pollutants, such as O3 and secondary aerosols, are formed via oxidation of NOx and VOCs by hydroxyl radicals (OH·). Latest researches show that in addition to OH·, Cl· also plays an important role in urban atmospheric chemistry, which could have a significant impact on the atmospheric oxidation capacity and thus the formation of ozone, nitrate and secondary organic aerosols. Existing field observations show that the concentration of Cl2 in urban areas of China is much high; especially in coastal regions, the sources of chlorine are quite complicated; the importance of chlorine chemistry in urban air pollution in China has been gradually confirmed by field campaigns. However, the chlorine chemistry within numerical models is quite simple, researches on emissions of chlorine precursors and their influences on air pollution formation are very limited, which restricts further understanding of the underlying mechanisms of air pollution in coastal city clusters. In this project, we plan to develop an emission inventory of chlorine precursors for the Yangtze River Delta region, develop the chlorine chemistry that is applicable to China's coastal city clusters within three-dimensional numerical model, and explore the impacts of chlorine chemistry on the formation of O3, nitrate and SOA as well as the control path of secondary air pollutants. This study will provide basic theories to China's air pollution control.