北京地区大气中VHCs观测结果的初步分析

采用Tenax TA和碳分子筛吸附富集— 热脱附— 毛细管柱气相色谱法, 测定了北京地区大气中C2～C10可挥发性烃类化合物(简称VHCs)的浓度变化。从2001年9月到2003年8月, 先后采集到有效样品113个。检出55个VHCs组分, 其中烷烃26个, 烯烃19个,芳香烃10个。TVHCs的平均浓度为364.3 ±99.3 μg/ m3;11月份浓度最高, 为546.9 ±353.5 μg/m3, 8月份浓度最低, 为251.8 ±152.4 μg/m3;采暖季比非采暖季高30%, 城区比郊区高10%;有明显的日变化。初步分析发现, 机动车尾气排放和天气气象条件是造成北京地区大气VHCs污染的两个最主要因素。

The Preliminary Study on Measured Results of Ambient VHCs in Beijing Areas

The variation of atmospheric concentration of C2～C10 volatile hydrocarbon compounds (VHCs)is measured out in Beijing areas using Tenax TA and Carbosieve sorption-thermodesso rption-capillary gas chromatography.113 samples are collected during the period of September 2001 to August 2003.55 VHCs species are detected including 26 alkanes, 19 alkenes and 10 aromatics.The average mass concentration of VHCs is 364.3 ±99.3 μg/m3. The seasonal peak value is 546.9 ±353.5 μg/m3w hich appears in autumn.The valley value appears in summer which is 251.8 ±152.4 μg/m3.The VHCs average concentration is 30% in the heating season more than that in the non-heating season.The average concentration in the urban area is 10% higher than that in the suburbs.There are the significant daily variations of VHCs in Beijing.Results show that the polluted levels of ambient air depended mainly on the vehicle emissions and the meteorological conditions.