中文摘要：

2014年在北京市城市对照点定陵（城市背景点）、东四（城区点）和永乐店（东南区域传输点）3个不同功能站点进行了为期一年的大气挥发性有机物连续自动观测,测定了包括含氧VOCs在内的98种挥发性有机物,系统分析了北京地区大气VOCs的组成特征、时空分布特征及大气化学活性.结果表明,北京市大气VOCs的年均体积分数为（47.36±13.78）×10-9,化学组成以烷烃为主,占39.55%,其次是OVOCs,再次是烯烃和芳香烃.中心城区点和东南区域传输点的VOCs浓度水平显著高于城市背景点.中心城区点VOCs受交通源和生活燃气排放影响显著,东南区域传输点受交通源和工业溶剂源影响显著,而城市背景点则受上风城区传输影响大.总VOCs浓度季节变化整体表现为冬高、夏低的特点.受污染来源的差异影响,不同点位的不同组分表现出并不相同的日变化特征.甲苯/苯的比值分析显示,北京地区冬季采暖期燃煤影响突出,春夏季溶剂挥发贡献增加.北京VOCs大气化学活性以烯烃为主,其次是芳香烃和OVOCs,关键活性组分有乙烯、乙醛、间/对-二甲苯、甲苯、丙烯、邻-二甲苯、乙苯、正丁烷、1-丁烯和丙醛等.

英文摘要：

Ambient concentrations of 98 volatile organic compounds（VOCs） species were measured continuously at Dingling（DL, background site）, Dongsi（DS, urban site） and Yongledian（YLD, southeast regional transmission site） in Beijing for one year in 2014, to better understand the characterization of VOCs and their role in chemical reactivity in Beijing. The annual concentration of VOCs in Beijing was（47.36±13.78）×10-9, with alkanes as the most abundant group（39.55%）, followed by oxygenated VOCs（OVOCs）, and then alkenes and aromatics. The VOCs concentrations at DS and YLD were much higher than those at DL. DS was heavily influenced by vehicular emissions and the usage of LPG/NG, YLD had great contribution of vehicular emissions, paint and solvent evaporation, while DL had more influence of urban pollution transportation. The seasonal variation of VOCs showed maximum in winter and minimum in summer. Because of the different emission sources, VOCs species at 3 sites exhibited different diurnal variations. The ratios of T/B（toluene/benzene） indicated that coal combustion had great contribution to VOCs during winter, while contribution of paint and solvent evaporation increased in spring and summer. Alkenes played a predominant role in VOCs chemical reactivity, followed by aromatics and OVOCs. And the key reactive VOCs species in Beijing were ethene, acetaldehyde, m/p-xylene, toluene, propene, o-xylene, ethylbenzene, n-butane, 1-butene, and propanal.