天津中心城区环境空气挥发性有机物污染特征分析

为研究天津中心城区挥发性有机物的污染特征,在天津中心城区布点26个,分别对春、夏、秋、冬四季进行了系统采样.天津中心城区共检出挥发性有机物80余种,检出率大于80%的物质主要为烷烃、苯系物和卤代烃.天津中心城区挥发性有机物总浓度(体积分数,下同)季节变化特征为:春季(110.43×10-9)>秋季(93.73×10-9)>冬季(73.37×10-9)>夏季(60.43×10-9).统计结果表明,城区挥发性有机物总浓度主要集中在30×10-9~90×10-9之间,在此区间4个季节的样品百分比均在50%以上.天津中心城区不同季节VOCs组成存在一定差异.含氧有机物和烷烃是VOCs主要组成物质,两者浓度百分比之和4个季节均在50%以上.对苯系物和卤代烃这两类主要污染物,进行了季节变化分析.

Pollution Characterization of Volatile Organic Compounds in Ambient Air of Tianjin Downtown

To study the pollution characteristics of volatile organic compounds(VOCs) in Tianjin downtown ambient air, 26 sampling points were distributed in Tianjin and systematic sampling was carried out in Spring, Summer, Autumn and Winter, respectively. More than 80 kinds of VOCs were detected which mainly included alkanes, BETX and halohydrocarbon with detection rates of over 80%. The total concentration of VOCs changed with the seasons, in the order of Spring (110.43×10^-9) > Autumn (93.73×10^-9) > Winter (73.37×10^-9) > Summer (60.43×10^-9). The result of concentration statistics indicates that the total concentration of VOCs in urban areas was in the range of 30×10^-9-90×10^-9 and the number of samples in every season in this concentration range accounted for over 50%. There were also differences in the composition of VOCs with the change of seasons in Tianjin. Oxygenated organic compounds and hydrocarbons were the main substances of VOCs and the concentration percentage of them was over 50% in every season. Two main pollutants, BETX and halohydrocarbon, were analyzed for seasonal variation in this paper.