北京市大气中VOCs垂直分布的航测研究  

The measurement of vertical distribution of airborne VOCs mixing ratios in Beijing

作　　者：王思源[1] 邵敏[1] 王玮[2] 

机构地区：[1]北京大学环境科学与工程学院 环境模拟与污染控制国家重点联合实验室,北京100871 [2]中国环境科学研究院,北京100012

出　　处：《中国环境科学》2009年第7期679-684,共6页China Environmental Science

基　　金：国家自然科学基金资助项目(40575059)

摘　　要：2007年8月在北京市地表水平及地表以上900～3100m采集全空气样品,并用气相色谱(GC-FID)-质谱(MS)对样品中的50种挥发性有机物(VOCs)组分进行了定量分析,研究了北京市大气VOCs的垂直分布特征,并识别了当地排放与周边地区的输送作用对大气VOCs的相对贡献.结果表明,随着高度的增加,各类VOCs浓度均呈现显著降低的趋势,不同物种浓度的垂直梯度与其大气化学活性直接相关.此外,湍流扩散和输送作用也会影响VOCs浓度的垂直梯度.通过对观测期间北京市上空气团反向轨迹的反演以及对惰性VOCs物种的垂直贡献的分析发现,北京市低对流层内大气VOCs受局地源排放主导,亦可能受到天津以及河北廊坊等污染地区的影响.The whole air samples at ground level and in the layer between 900m and 3100m over Beijing City were collected in August 2007. Up to 50 volatile organic compounds （VOCs） species were quantified by using GC-FID/MS. Vertical profiles of VOCs and their chemical speciation were analyzed and influence of local emissions and regional transport on the measured VOCs was studied. VOCs concentration decreased significantly with the increase of altitude. The different vertical patterns of VOCs species were due to their atmospheric chemical reactivities, while atmospheric diffusion and long range transport might also affect the vertical distribution of VOCs. By investigating the backward trajectories and the variation of the relative abundance of long-lived VOCs species, the airborne VOCs were found to be mainly from the diffusion of local emissions, and also influenced by the plume transported from eastern and southern regions, e.g. Tianjin and Langfang cities, under some conditions.

关 键 词：挥发性有机物(VOCs) 垂直分布 局地排放 输送作用 

分 类 号：X511[环境科学与工程—环境工程]