大气硝酸盐光化学反应对硫酸盐非均相生成的影响及机制研究

硫酸盐气溶胶对空气质量、大气气候和人类健康有着重要影响，但目前对于硫酸盐气溶胶生成机制的认识还有待完善。SO2在大气颗粒物表面的非均相反应是硫酸盐形成的有效途径。以往的研究主要集中在大气颗粒物中单一组分界面或大气中共存污染物作用下SO2的非均相氧化，而关于颗粒物表面化学老化过程对硫酸盐非均相生成的影响和机制研究还十分有限。因此，本项目将在矿尘、腐殖酸和实际采集的真实大气颗粒物PM2.5表面系统研究硝酸盐的界面光化学反应对硫酸盐非均相生成的作用；考察环境因素和颗粒物化学组成对反应动力学的影响；揭示和阐明硝酸盐界面光化学反应影响硫酸盐非均相形成的反应机制。本研究有助于全面认识硫酸盐气溶胶的形成途径，同时为大气化学模式的优化和区域污染的有效防控提供理论依据。

Atmospheric sulfate aerosols have important impacts on air quality, climate, and human health. However, the sulfate formation mechanism has not been fully understood. Heterogeneous oxidation of SO2 is an effective production pathway of sulfate in the atmosphere. Previous studies mainly focused on the heterogeneous oxidation of SO2 on a single component of atmospheric particles or the synergistic effect of co-existed pollutant gases. However, the impact of aerosol chemical aging on heterogeneous sulfate formation is not clear. Therefore, this project will conduct laboratory studies to systematically investigate the role of nitrate photochemistry in heterogeneous reaction of SO2 on mineral dusts, humic acids and authentic PM2.5 particles. The influences of environmental factors and chemical composition of aerosol particles on the reaction kinetics will be explored. And the mechanisms of heterogeneous sulfate formation during nitrate photolysis will be revealed. This study will develop a more comprehensive understanding of sulfate formation mechanism in the atmosphere and provide important information for the optimization of current atmospheric models as well as the effective control of air pollution.