Cao Han-Yu, Pan Yue-Peng, Wang Hui, Tan Ji-Hua, Wang Yue-Si
College of Forestry, Gansu Agricultural University, Lanzhou 730070, China.
Huan Jing Ke Xue. 2013 Jun;34(6):2065-70.
Benzene, toluene, ethylbenzene and dimethylbenzene are typical anthropogenic emitted organics in the atmosphere, which not only endanger human health but also actively participate in photochemical reactions, generating O3 and secondary organic aerosols. In order to investigate the pollution level and its ozone formation potentials, concentrations of BTEX and O3 were parallel measured by the passive sampler and analyzed using GC-MS and ICS-90 during 2008-2010 in urban Beijing. The results show that toluene was the most abundant compound (8.7 +/- 3.1) microg x m(-3), followed by benzene, ethylbenzene and m/p-xylene, with concentrations of (7.1 +/- 3.3), (4.2 +/- 1.4) and (3.4 +/- 1.5) microg x m(-3), respectively. Concentrations of BTEX peaked in winter, followed by autumn, summer, and spring, with values of (26.8 +/- 12.1), (25.9 +/- 4.9), (24.7 +/- 2.8) and (16.8 +/- 1.4) microg x m(-3), respectively. Benzene concentrations were the highest in winter, while for toluene, the concentration was higher in summer than that in winter. Based on the maximum incremental reactivity scale, m/p-xylene was found to be the dominant contributor to ozone formation among BTEX. The ozone formation potentials of BTEX in Beijing were 65.2, 60.2, and 75.7 microg x m(-3) in 2008, 2009, and 2010, respectively, which were consistent with the measured values of 80.5, 65.0, and 101.9 microg x m(-3) during the corresponding period. Vehicular emission and solvent evaporation were the major sources of BTEX. Concentrations of benzene were affected by coal heating in winter, whereas BTEX concentration was more influenced by solvent evaporation in summer, which had an important contribution to the formation of O3 in urban Beijing.
苯、甲苯、乙苯和二甲苯是大气中典型的人为排放有机污染物，它们不仅危害人体健康，还积极参与光化学反应，生成臭氧和二次有机气溶胶。为了研究污染水平及其臭氧生成潜力，2008 - 2010年期间在北京城区使用被动采样器对苯系物（BTEX）和臭氧的浓度进行了同步测量，并采用气相色谱 - 质谱联用仪（GC - MS）和离子色谱仪（ICS - 90）进行分析。结果表明，甲苯是含量最高的化合物，浓度为(8.7 ± 3.1) μg·m⁻³，其次是苯、乙苯和间/对二甲苯，浓度分别为(7.1 ± 3.3)、(4.2 ± 1.4)和(3.4 ± 1.5) μg·m⁻³。BTEX浓度在冬季达到峰值，其次是秋季、夏季和春季，浓度分别为(26.8 ± 12.1)、(25.9 ± 4.9)、(24.7 ± 2.8)和(16.8 ± 1.4) μg·m⁻³。苯浓度在冬季最高，而甲苯浓度夏季高于冬季。基于最大增量反应活性尺度，发现间/对二甲苯是BTEX中对臭氧生成的主要贡献者。北京地区2008年、2009年和2010年BTEX的臭氧生成潜力分别为65.2、60.2和75.7 μg·m⁻³，与同期测量值80.5、65.0和101.9 μg·m⁻³一致。机动车排放和溶剂挥发是BTEX的主要来源。苯浓度受冬季煤炭取暖影响，而BTEX浓度夏季受溶剂挥发影响更大，溶剂挥发对北京城区臭氧形成有重要贡献。
