半挥发性有机污染物（SVOCs）在气态和颗粒态之间的分配决定了其在大气中的环境行为，如远距离传输和干湿沉降等，所以，气粒分配规律的研究对于SVOCs的污染控制具有重要科学意义。本项目将以大气中典型SVOCs—多环芳烃（PAHs）为目标物，分别从气粒分配规律的地区差异性、年际变化特征和采样方案影响等3个方面，阐明PAHs气粒分配规律的影响因素和内在量化关系，建立计算PAHs气粒分配系数的经验公式和理论公式，并且利用监测结果对公式进行优化，实现其对不同地区、不同温度、不同PAHs的气粒分配系数的准确预测，进一步完善PAHs的气粒分配理论，为研究大气中PAHs的环境行为提供有力工具。

The environmental fate of semivolatile organic compounds (SVOCs) in atmosphere mainly depends on their distribution between the gas and the particle phase, such as long range atmospheric transport, dry and wet deposition. Therefore, the study on the mechanism of gas-particle partitioning of SVOCs has important scientific significance for the pollution control of SVOCs. In this project, polycyclic aromatic hydrocarbons (PAHs) are chosen as the typical SVOCs for the study of gas-particle partitioning. The influences on gas-particle partitioning will be comprehensively investigated in three aspects: the difference among sites, the annual variation, and the influence of sampling design. Furthermore, their relationships among influences of these factors will be studied and quantized. Accordingly, an empirical equation and a theoretical equation will be established for the calculating of the gas-particle partition coefficient of PAHs. The monitoring results will be used for the optimization of the two equations in order to make the exact prediction of the gas-particle partition coefficient of different PAHs in different temperatures and different regions. This project will further improve the gas-particle partitioning theory of PAHs. Furthermore, the derived equations will provide a powerful tool for the study of environmental fate of PAHs in atmosphere.