北京地区城乡结合部大气挥发性有机物污染及来源分析

采用低温固体吸附采样,热脱附-气相色谱-质谱方法对北京城乡结合地空气中挥发性有机物（VOCs）进行了观测分析,对城乡结合地空气中挥发性有机物含量水平、时空变化、来源等进行了研究.所有样品共检测出挥发性有机物265种,挥发性有机污染物的平均浓度为431.7μg·m-3,苯系物和烷烃是本地区大气环境中含量最为丰富的挥发性有机物,浓度分别为248.1μg·m-3和130.5μg·m-3,烯烃11.7μg·m-3,卤代烃22.4μg·m-3,含氧化合物18.6μg·m-3,所占比例分别为57.0%、30.0%、3.0%、6.0%和4.0%;苯、甲苯、乙苯、二甲苯等是含量较高的物质;有机污染物在交通早、晚高峰时期出现较高浓度水平,VOCs浓度冬季最高,秋季次之,夏季最低;源分析表明空气中挥发性有机物的主要来源有机动车尾气,油气挥发排放,黏结剂和溶剂利用以及植被排放等,贡献率分别为53.4%、20.1%、11.0%和5.93%.

Pollution and Source of Atmospheric Volatile Organic Compounds in Urban-rural Juncture Belt Area in Beijing

A method for determining volatile organic compounds(VOCs) by cryogenic dynamic adsorption in solid adsorbent tubes,subsequent thermal desorption with cryofocusing in a cold trap and analysis by gas chromatography and mass spectrometry was adapted.Volatile organic content levels,spatial and temporal distribution and sources were studied.Results indicated that 265 species were detected in atmospheric environment of this area,including alkanes,alkenes,aromatics,halohydrocarbons and oxygenated compounds.The ave...