长沙市环境空气中BTEX的污染特征及健康风险

BTEX(苯、甲苯、乙苯、二甲苯等)是对空气质量和人体健康具有重要影响的挥发性有机物.为研究长沙市城市大气BTEX污染特征,选择2个典型城市站点(采样点S和W)于2017年8月进行了连续采样分析.结果显示:2个采样点BTEX平均浓度分别为(9.84±5.44),(6.35±4.68)μg/m3;其中间/对-二甲苯是占比...

POLLUTION CHARACTERISTICS AND HEALTH RISKS OF BTEX IN AMBIENT AIR OF CHANGSHA

BTEX(benzene, toluene, ethylbenzene, xylenes, etc) are volatile organic compounds which have great impact on air quality and human health. To study pollution characteristics of BTEX in Changsha, ambient samples were collected and analyzed consecutively at two typical urban sites(site S and W) during August 2017. The results showed that the averaged concentrations of BTEX were(9.84±5.44) μg/m3 at site S and(6.35±4.68) μg/m3 at site W, respectively; and m, p-xylenes were the most abundant species among BTEX with contributions of 32.3% and 26.7%, respectively, followed by toluene with contributions of 20.6% and 22.8%, respectively. Diurnal variations of major BTEX species showed a “U” pattern with lower concentrations during 13:00—14:00 and higher concentrations during 7:00—8:00 and 16:00—17:00, which might be influenced by variation of photo-chemistry reactivity and source emission. The correlations among BTEX and relative proportions of benzene, toluene and ethylbenzene suggested that traffic-relate sources, industrial sources and solvent emissions were the major sources of ambient BTEX in Changsha. The non-carcinogenic hazard quotients of BTEX(2.89×10-4~9.35×10-2) were all lower than 1, indicating no obvious adverse carcinogenic hazard risk on the exposed population. However, the carcinogenic hazard risk values of benzene(6.41×10-6and 5.34×10-6) were higher, implying the potential cancer risks due to ambient benzene exposure in the study region.