北京东南郊大气中多环芳烃的沉降

Atmospheric Polycyclic Aromatic Hydrocarbons and Deposition in the Southeastern Suburb of Beijing

对2005年3月─2006年1月北京市东南郊气相、总悬浮颗粒物（TSP）以及降尘样品中16种优控PAHs分析发现,降尘样品中2~3环PAHs组分占优势地位,其构成比例与TSP和气相样品差异较大;比较不同采样点、各季节的PAHs沉降速率,对样品中PAHs组分构成比例的特点给予解释,推断PAHs的沉降行为受气象条件、沉降点周围污染源强度以及下垫面性质等因素的影响;对PAHs月均沉降通量与ρ（PAHs）进行相关分析,建立PAHs月均沉降通量与TSP中PAHs总浓度之间的回归方程.

Gas phase, TSP and dustfall samples were collected in the southeastern suburb of Beijing from March, 2005 to January, 2006, and concentrations of 16 USEPA priority PAHs in all samples were analyzed. 2 - 3 ring compounds were dominating in dustfall samples, and significant differences existed between the composition patterns of PAHs in the dustfall samples and TSP and gas phase samples. Based on the comparison of the deposition velocities in different sites and seasons, the characteristics of the PAH composition patterns in different phases could be explained. Impact factors such as the conditions of weather, pollution level and sources, as well as the conditions of the sampling sites could influence the deposition level. A regressive equation between the mensal PAHs fluxes and mass concentrations of PAHs in TSP was put forward after correlation analysis.