挥发性有机物（VOC）排放至大气后发生一系列复杂的大气物理化学过程，一方面，VOC与臭氧、氢氧自由基等氧化剂发生气相氧化反应，影响大气氧化潜势，另一方面，VOC经过气相氧化和复杂的非均相物理化学过程导致二次有机气溶胶（SOA）的生成。从而对区域灰霾天气的形成和全球尺度的大气化学都有着重要影响。本项目拟结合烟雾箱反应系统和在线流动反应体系，采用质谱、红外、拉曼光谱学分析以及颗粒物表面物理化学性质表征等技术手段，结合加湿串联差分迁移分析仪、光腔衰荡光谱等粒径以及光学分析手段，开展接近大气实际环境浓度条件下的VOC的大气化学转化和演化过程研究，获取反应动力学基础数据，认识VOC均相和非均相的大气化学转化机制，揭示SOA的生成机制，研究SOA的吸湿、光学特性并探索吸湿过程对灰霾形成的影响。通过深入分析VOC大气化学转化过程对灰霾形成的影响，为我国城市和区域污染治理工作提供理论基础和科学依据。

Volatile organic compounds (VOC) are numerous, varied, and ubiquitous gaseous pollutions in the environment. Once emitted, VOC undergo a series of complicated physical and chemical processes in the atmosphere. On one hand, VOC could be oxidized by atmospheric oxidants (such as hydroxyl radicals and ozone) and influence the concentrations of oxidants, hence leading to the change of atmospheric oxidation capacity. On the other hand, VOC serve as a source of atmospheric secondary organic aerosol (SOA) through the heterogeneous reactions and homogeneous oxidation. VOC atmospheric oxidation processes not only contribute to the formation of regional haze, but also play a role in the global atmospheric chemistry. This project tries to carry out researches for atmospheric VOC chemical transformations and evolutions under real atmospheric conditions by utilizing smog chamber reaction system and online flow reaction system. The gas-phase and particle-phase products will be indentified by Mass, Infrared and Raman spectroscopy as well as the testing techniques for physical and chemical properties of particles. The hygroscopic characters and optical properties of SOA particles will be analyzed by hygroscopic tandem differential mobility analyzer and cavity ring-down spectroscopy.We seek to acquire basic reaction kinetics data, get a better understanding of VOC homogeneous and heterogeneous chemical conversion mechanisms, and reveal the formation mechanism of SOA. This project aims at investigating the hygroscopic characters and optical properties of SOA particles and exploring the roles they play during the haze formation. We attempts to analysis the impact of VOC chemical conversion process during the haze formation, thus providing theoretical results and scientific basis for the abatement work of air pollution in metropolitan areas.