太原公共场所空气中挥发性有机物的暴露特征

采用苏玛罐采样,预浓缩Entech 7100-Agilent 7890A GC/5975C MSD联用系统分析,分析太原市5个居民休闲公共场所非周末与周末时段空气中VOCs(挥发性有机物)的暴露特征. 结果表明:全部样品中51种VOCs均有检出,总平均暴露水平为94.83 μg/m3,ρ(烷烃)、ρ(芳香烃)和ρ(烯烃)最高,三者分别占ρ(总VOCs)的47.27%、43.40%和9.33%. 苯暴露水平为5.22 μg/m3,是欧盟规定的环境空气中ρ(苯)年均值的1.04倍. VOCs暴露水平在儿童公园(为151.39 μg/m3)最高,在龙潭公园 (64.55 μg/m3)最低. 这可能与儿童公园位于太原市最大商业区且周围建筑密集污染物不易扩散,而龙潭公园周围地势开阔污染物易扩散有关. 儿童公园周末时段VOCs的暴露水平明显大于非周末时段,反映了人为活动对环境空气中VOCs的影响. 太原市公共场所非周末与周末时段的VOCs非致癌风险系数较低；周末时段空气中苯对人体的致癌风险(8.44×10-7)是非周末时段(3.39×10-7)的2.49倍,但均未超过苯的人体致癌风险值(1.0×10-6). 来源分析显示,燃煤和机动车尾气排放是太原市公共场所空气中VOCs的主要来源. 

Exposure Characteristics of Atmospheric Toxic Volatile Organic Compounds to Populations in Public Places in Taiyuan, China

Exposure characteristics of atmospheric volatile organic compounds (VOCs) in public exercise and recreational places during workdays and weekends in Taiyuan were explored by SUMMA canisters for air sampling, and Entech 7100-Agilent 7890A gas chromatography/5975C mass selective detector (GC-MSD) for analysis. A total of 51 species of VOCs were identified, including alkanes (47.27%), aromatics (43.40%) and alkenes (9.33%), respectively. The average exposure of total VOCs of target compounds was 94.83 μg/m3 in all five places. The exposure level of benzene in Taiyuan (5.22 μg/m3) exceeded the annual concentration standard (5 μg/m3) required by the European Community, which is higher than that in many domestic and foreign cities. The highest and lowest VOCs exposure levels were found in Children's Park (151.39 μg/m3) and Longtan Park (64.55 μg/m3), respectively. The differences may attribute to the different geographic characteristics of the two places. Children's Park is located in the largest business district in Taiyuan, and is surrounded by dense construction, which severely prevents the dispersion of air VOCs pollutants, while the open terrain of Longtan Park benefits their spread. The exposure levels of VOCs in Children's Park were significantly higher during weekends than workdays, reflecting the influence of human activities on the exposure level of VOCs in the atmosphere. Based on the four-step evaluation model of health risk assessment, volatile pollutants would not cause non-carcinogenic health to the exposed population on the workdays and weekends. The benzene-associated cancer risk on the workdays (3.39×10-7) and weekends (8.44×10-7) were lower than that recommended by US EPA (1.0×10-6). Source identification by analyzing the concentration ratios of the typical compounds indicated that atmospheric VOCs in public places in Taiyuan were mainly from coal combustion and vehicle exhaust emissions.