Dehhaghi Sam, Hasankhani Hossein, Taheri Ahmad
Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran.
Tehran Air Quality Control Company, Tehran Municipality, Tehran, Iran.
Stoch Environ Res Risk Assess. 2023 May 26:1-17. doi: 10.1007/s00477-023-02476-3.
This study examined the concentration of BTEX in Tehran from 2018 to 2020 in five monitoring stations with different backgrounds, which has been accomplished using the combination of passive sampling and GC-FID method. The total concentration of BTEX was estimated to be 65.39 (µg/m), with a higher average concentration in 2019-2020 (77.79 µg/m) compared to 2018-2019 (53.48 µg/m) due to the leaping concentration of Toluene in the pandemic era. Despite a Benzene concentration decline in recent years, the average annual concentration of Benzene (5.66 µg/m) at five stations remained higher than the EU commission and India standards (5 µg/m) as well as Japan and Iraq thresholds (3 µg/m). Toluene dominated other species in terms of concentrations, mass distribution (0.6%), followed by m,p-Xylene (0.2%), Benzene (0.05-0.1) and Ethylbenzene (< 0.05). The evidence regarding seasonal changes of BTEX in 2019 shows the maximum concentration of these compounds in autumn, which is probably due to heavier traffic compared to other seasons. In contrast, in the first half of 2020 (which encompasses the start of the pandemic period and urban lockdown), point sources seem to play a prominent role in concentration fluctuations, as confirmed by changes in interspecies relationships and lower traffic congestion. The highest mean concentrations were observed in high-traffic, residential and suburban sites, respectively. The study reveals that m,p-Xylene possess the highest Ozone formation potential (109.46), followed by Toluene (85.34), o-Xylene (46.87), Ethylbenzene (13.52) and Benzene (2.61). Health risk assessment results indicated the high carcinogenic risk of Benzene (mean = 3.6 × 10) and the acceptable non-carcinogenic risk of BTEX (hazard index~0.03 < specified limit of 1). Finally, the estimated weighted exposures of BTEX emphasized that residents near the high-traffic districts are more exposed to BTEX.
The online version contains supplementary material available at 10.1007/s00477-023-02476-3.
本研究于2018年至2020年期间，在德黑兰五个背景不同的监测站，采用被动采样与气相色谱 - 火焰离子化检测法相结合的方式，对苯系物（BTEX）的浓度进行了检测。BTEX的总浓度估计为65.39（μg/m），由于大流行时期甲苯浓度的跃升，2019 - 2020年（77.79 μg/m）的平均浓度高于2018 - 2019年（53.48 μg/m）。尽管近年来苯浓度有所下降，但五个监测站的苯年均浓度（5.66 μg/m）仍高于欧盟委员会和印度标准（5 μg/m）以及日本和伊拉克的阈值（3 μg/m）。就浓度和质量分布而言，甲苯占主导地位（约0.6%），其次是间、对二甲苯（约0.2%）、苯（约0.05 - 0.1）和乙苯（<0.05）。2019年BTEX季节变化的证据表明，这些化合物在秋季浓度最高，这可能是由于秋季交通量比其他季节更大。相比之下，在2020年上半年（涵盖大流行开始和城市封锁时期），点源似乎在浓度波动中起主要作用，这一点通过物种间关系的变化和较低的交通拥堵得到证实。最高平均浓度分别出现在交通繁忙、居民区和郊区。该研究表明，间、对二甲苯具有最高的臭氧生成潜力（约109.46），其次是甲苯（约85.34）、邻二甲苯（约46.87）、乙苯（约13.52）和苯（约2.61）。健康风险评估结果表明，苯具有高致癌风险（平均值 = 3.6×10），而BTEX具有可接受的非致癌风险（危害指数约0.03 <规定限值1）。最后，BTEX的估计加权暴露强调，交通繁忙地区附近的居民接触BTEX的程度更高。
在线版本包含可在10.1007/s00477 - 023 - 02476 - 3获取的补充材料。
