有机硫酸酯(OS)和有机硝酸酯(ON)是大气二次有机气溶胶的重要组分，主要由大气中异戊二烯、α-蒎烯等挥发性有机污染物与OH、SO2、NOx等自由基、活性分子反应形成。有机硫酸酯和有机硝酸酯在大气中广泛存在，其可通过氧化反应或气粒分配进入颗粒相，影响新粒子的形成，从而对空气质量、气候变化和人体健康等产生不利影响，引起了大气化学研究者的广泛关注。本项目拟采用高水平量子化学计算和分子模拟的方法研究典型有机硫酸酯与典型有机硝酸酯类化合物在大气环境中的形成机理，并阐明有机硫酸酯与有机硝酸酯在硫酸和有机酸等存在下参与的成核机理；从分子水平上探讨其结构信息、形成机理、中间产物等；寻找形成的分子团簇中临界核的化学组成、分子数目及半径大小；总结有机硫酸酯与有机硝酸酯参与成核的规律，建立预测模型，为正确认识大气二次气溶胶的形成机制及治理大气污染和环境立法提供强有力的理论依据和科技支撑。

Organosulfates (OS) and Organonitrates (ON), the important components of secondary organic aerosols, are mainly formed by the reactions of volatile organic compounds, such as isoprene and α-ponene, with free radicals and active molecules, such as OH, SO2 and NOx, in the atmosphere. Organosulfates and organonitrates are widely present in the atmosphere. They can enter the particle phase through oxidation reactions or gas-particle distribution and then affect the new particle formation, which has adverse effects on air quality, climate change and human health. Therefore, they have been arisen the wide attention of researchers on the atmospheric chemistry. This project intends to study the formation mechanism of organosulfates and organonitrates in the atmosphere and clarifies the nucleation mechanism of organosulfates and organonitrates in the presence of sulfuric acid and organic acids by using high-level quantum calculation and molecular simulation. The geometrical parameters, formation mechanism and intermediates will be obtained from the molecular level at the this project. The chemical composition, number of molecules and radius of the critical nuclei in molecular clusters will be obtained at molecular level. This project will summarize the laws of organosulfates and organonitrates participating in nucleation and establish prediction models. As a result, this project will contribute to complement the formation mechanisms of aerosols with the participation of sulfates and nitrates in the clouds and droplets. We hope that this project will find out more effective control strategies of the air pollution and be of practical value for the environmental planning and environmental legislation.