大气颗粒物中多环芳烃的粒径分布

Particulates Size Distribution of Polycyclic Aromatic Hydrocarbons in the Ambient Air of Beijing

用GC／MS法测定了北京市北部的城乡结合部和远郊区的大气颗粒物中的16种优控多环芳烃（PAHs）的浓度。采样时间从2003年1月到11月，分季节采样。采样器采集的大气颗粒物粒径分为5段，粒径范围从小于等于1．1μm到100μm。对颗粒物中的总优控PAHs和检测出的单一优控PAHs在不同地区、不同时期的粒径分布进行了比较和讨论。总优控PAHs和单一优控PAHs化合物均趋向于吸附在小粒径颗粒物中，占总量47％～65％的总优控PAHs分布在粒径小于1．1μm的颗粒物中，只有不到10％的总优控PAHs分布在粒径大于7．0μm的粗颗粒物上。

The concentration of 16 priority PAHs in the ambient air of a urban border site and a exurb site was determined respectively. Atmospheric particle were sampled from January 2003 to November 2003, during the winter and summer, in the north of Beijing. The particle size was divided into 5 stages and the size ranges covered were from less than 1.1 to 100 μm. The particle size distribution of total priority PAHs and individual priority PAHs in the ambient air of urban border site and exurb site were compared and discussed. Both total priority PAHs and the individual priority PAHs lean to be absorbed in the small - size atmospheric particle, 47 % - 65 % of the total priority PAHs content was found on particles smaller than 1.1 μm,but the total priority PAHs content on the big particles bigger than 7.0 μm was less than 10%.