西安市交通主干道环境空气中苯系物的污染特征与健康风险评价

发布时间：2018-04-26 08:12

本文选题：西安市 + 苯系物　；参考：《西北大学》2017年硕士论文

【摘要】：随着我国经济持续、稳定、快速的发展,人民群众的生活水平有了大幅提高,城镇化建设也得到了快速发展。但在经济高速发展的同时,城市环境空气污染在不断加剧,这给人们身体健康带来了一系列的危害。挥发性有机物(VOCs)是环境空气中众多污染物中的一类,因其自身的毒性以及是臭氧、二次有机气溶胶的重要前体物,受到国内外学者的广泛关注和深入研究。苯系物是挥发性有机物的重要组分,因其引发的环境效应和对人体的危害而受到了高度的重视。随着城市汽车保有量不断增长,交通源排放的苯系物在不断增多,交通主干道环境空气的污染情况越来越严重。本文利用活性炭吸附/二硫化碳解吸-气相色谱法对西安市具有代表性的两处交通主干道的环境空气进行了监测,分析研究了交通主干道环境空气中苯系物(苯、甲苯、乙苯、二甲苯)的污染水平、组成特征、季节和日变化规律、化学反应活性和健康风险评价。结果表明,长安路和大庆路环境空气中苯系物的年均总质量浓度分别为42.30、31.80μg·m-3,大庆路空气中苯、甲苯、乙苯、间-对二甲苯、邻二甲苯年均质量浓度分别为 11.05、12.28、6.04、9.05、3.89μg·m-3,长安路分别为 10.40、8.31、4.12、5.85、3.13μg·m3。机动车尾气排放和化石燃料燃烧排放是两处研究区的主要污染源。大庆路和长安路空气中苯系物总浓度大小季节变化为冬秋春夏。苯系物各物质浓度普遍冬季最高,秋春季其次,夏季最低,这与气象条件、光化学反应和污染源排放有关。日变化特征显示,大庆路冬春秋季苯系物浓度早中晚较高,这与交通高峰期机动车排放以及餐饮业高峰期燃料燃烧排放有关。夏季早晚浓度较高,中下午浓度较低,快速的光化学反应消耗和大气对流扩散有效的降低了空气中苯系物的浓度。长安路苯系物冬秋季日变化特征呈“W”(三峰)型,早中晚浓度较高,春夏季浓度高峰出现在早上和晚上。18:00后,长安路环境空气中苯系物浓度变化趋势与大庆路不同,长安路呈上升趋势,大庆路呈下降趋势,这与气象因素和人民的生活出行习惯有关。化学反应活性研究结果表明,间-对二甲苯始终是OH消耗速率最高的物质,苯的OH消耗速率最低。间-对二甲苯始终是臭氧生成潜势最高的物质。两处研究区苯系物总二次有机气溶胶生成潜势季节变化同为冬秋春夏,甲苯和间-对二甲苯普遍是四季中二次有机气溶胶生成潜势较高的物质。健康风险评价研究表明,大庆路和长安路环境空气中苯系物的非致癌风险危害指数分别为2.53E-01和2.21E-01,苯系物对两处研究区内的群众不存在非致癌风险。两处研究区苯的致癌风险值分别为4.31E-05和4.06E-05,说明苯对两处研究区内群众的身体健康存在致癌风险。
[Abstract]:With the sustained, stable and rapid development of China's economy, the living standards of the people have been greatly improved, and the construction of urbanization has also been rapidly developed. However, with the rapid development of economy, air pollution in urban environment is becoming more and more serious, which brings a series of harm to people's health. Volatile organic compounds (VOCs) are one of the many pollutants in the ambient air. Because of their own toxicity and the important precursors of ozone and secondary organic aerosols, VOCs have been widely concerned and deeply studied by scholars at home and abroad. Benzene is an important component of volatile organic compounds (VOCs). With the increasing of the amount of automobile in the city, the benzene compounds emitted from the traffic source are increasing, and the pollution of the air in the main road environment is becoming more and more serious. In this paper, the ambient air of two representative traffic trunk roads in Xi'an was monitored by activated carbon adsorption / carbon disulfide desorption gas chromatography. The benzene series (benzene, toluene, ethylbenzene) in the ambient air of traffic trunk roads were analyzed and studied. The pollution level, composition, seasonal and diurnal variation, chemical reaction activity and health risk assessment of xylene. The results showed that the average annual mass concentrations of benzene series in ambient air of Changan Road and Daqing Road were 42.30 ~ 31.80 渭 g m ~ (-3), respectively. The average annual mass concentrations of benzene, toluene, ethylbenzene, m-p-xylene, m-xylene and o-xylene in air of Daqing Road were 11.05 ~ 12.286.0 ~ (6.0) and 49.053.89 渭 g m ~ (-3), respectively, and Changan Road was 10.40 ~ 8.31 ~ 4.12 ~ (5.853.13) 渭 g / m ~ (-3), respectively. Motor vehicle emissions and fossil fuel combustion emissions are the main sources of pollution in the two study areas. The total concentration of benzene in the air of Daqing Road and Chang'an Road varies in winter, autumn, spring and summer. The concentrations of benzenes are generally highest in winter, followed by autumn and spring, and the lowest in summer, which are related to meteorological conditions, photochemical reactions and emissions from pollution sources. The diurnal variation shows that the concentration of benzene series in Daqing Road in winter spring and autumn is higher in the early middle and late hours which is related to the emission of motor vehicles during the peak period of traffic and the combustion of fuel during the peak period of catering industry. Higher concentration in summer and lower concentration in mid-afternoon, rapid photochemical reaction consumption and atmospheric convection diffusion can effectively reduce the concentration of benzene in the air. The diurnal variation characteristics of benzene series in winter and autumn of Chang'an Lu were "W" type with high concentration in the early, middle and late hours. The peak concentration of benzene series in spring and summer appeared in the morning and after .18: 00 in the evening. The change trend of benzene series concentration in the ambient air of Chang'an Road was different from that of Daqing Road. Changan Road is on the rise and Daqing Road is on the downward trend, which is related to meteorological factors and people's living and travel habits. The results of chemical reaction activity showed that m-p-xylene was always the highest OH consumption rate and benzene had the lowest OH consumption rate. M-p-xylene has always been the most potent ozone-forming substance. The seasonal variation of the total secondary organic aerosol formation potential in the two study areas is the same as that in winter, autumn, spring and summer. Toluene and m-xylene are generally the substances with high secondary organic aerosol formation potential in the four seasons. The results of health risk assessment showed that the non-carcinogenic hazard index of benzene series in the air of Daqing Road and Changan Road was 2.53E-01 and 2.21E-01 respectively, and there was no non-carcinogenic risk to the people in the two study areas. The carcinogenic risk values of benzene in the two study areas were 4.31E-05 and 4.06E-05respectively, which indicated that benzene had carcinogenic risk to the health of the people in the two study areas.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X513

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