三峡工程对库区生态环境的影响一直受到国内外的关注。同时，快速的城市化进程加剧了三峡库区大气细颗粒物（PM2.5）的污染。具有强致癌性的PAHs是大气中重要的一类有机污染物，然而目前对库区PAHs及其衍生物的污染缺乏全面的了解。本项目拟基于三峡库区典型城区和农村地区的观测，系统地研究大气中的PAHs及其衍生物（nitro-和oxy-PAHs），包括分析PM2.5中PAHs及其衍生物的污染水平、单体组成、时间序列与季节变化特征等；研究大气中PAHs及其衍生物的气粒分配及在颗粒物上的粒径分布特征；同时，探讨大气中PAHs及其衍生物的形成途径及气粒分配机制。本项目对认识大气中nitro-及oxy-PAHs的气相/颗粒相分配行为和深入揭示PM2.5的健康效应均有重要意义，且为库区大气毒害物控制决策提供科学依据。

Great attentions from environmentalists around the world have been paid to the ecological environment problems in the Three Gorges Reservoir area. On the context of fast urbanization, the fine particle (PM2.5) pollution in the area is increasing. PAHs which is strongly carcinogenic is an important organic pollutant in the atmosphere. However, little is known about the pollution characteristics of PAHs and their related derivatives in the Three Gorges Reservoir area. Thus, the aim of this project is to systematically study PAHs and related derivatives (nitro- and oxy-PAHs) in the atmosphere in typical urban and rural areas in the Three Gorges Reservoir area, including examine the concentration, congener profile and seasonal distribution of PAHs and related derivatives in PM2.5; investigate the gas/particle partitioning of PAHs and related derivatives in the atmosphere and size distribution in airborne particles; explore the formation mechanism and gas/particle partitioning mechanism. This project plays an important role in further understanding the gas/particle partitioning of nitro- and oxy-PAHs in atmosphere, besides, it’s significant for the revelation of the potential health effects of PM2.5 and the support for the air toxicants control decisions in the Three Gorges Reservoir area.