中文摘要：

本研究表征了2012年春季一次沙尘暴天气过程中京津冀地区大气可吸入颗粒物（PM10）的污染特征.借助PM10的水溶性元素、有机碳和元素碳的浓度,分析推断沙尘暴天气过程中矿物气溶胶对城市气溶胶污染的交汇叠加作用.使用中流量大气颗粒物采样器,于2012年4月1日～5月24日,在北京市西三环、天津空港经济区和张家口火车南站附近同时采集可吸入颗粒物（PM10）,采用离子色谱和元素碳/有机碳分析仪分析获取其水溶性离子、元素碳和有机碳浓度.结果表明,采样期间北京、天津和张家口这3个采样点PM10质量浓度的日均值分别为233.82、279.64和238.13μg·m^-3.4月27～29日,3个地区发生了沙尘暴天气,PM10质量浓度的最大日均值分别达755.54、831.32、582.82μg·m^-3.沙尘暴期PM10的有机碳（OC）浓度、二次有机碳（SOC）/OC的比值、硝酸根（NO3^-）和硫酸根（SO4^2-）浓度均高于非沙尘暴期间.采用电荷平衡计算证明沙尘暴期间大气颗粒物表明呈碱性,说明外来沙尘暴与本地污染相互叠加,矿物元素改变了颗粒物表面的酸碱性,沙尘暴和有机物发生耦合,促进了二次有机物的转化.

英文摘要：

Atmospheric particulate matter（PM10） was collected at sampling locations of Beijing,Tianjin and Zhangjiakou from April1 st to May 24 th,2012. The mass concentration of PM10 and concentrations of ions,elemental carbon（EC） and organic carbon（OC） in PM10 were determined. The results showed that average mass concentration of PM10 were 233. 82 μg·m- ^3for Beijing,279. 64 μg·m- ^3for Tianjin and 238. 13 μg·m^- 3for Zhangjiakou,respectively. Backward trajectories results confirmed dust storm events occurred from27 thto 29thApril. The maximum daily mass concentrations of PM10 were 755. 54 μg·m^- 3for Beijing,831. 32 μg·m^- 3for Tianjin and582. 82 μg·m^- 3for Zhangjiakou during the dust storm episodes,respectively. Water-soluble ions（Na^＋,NH4^＋,Ca^2 ＋,K^＋,F^-,Cl^-,NO^-3,SO^2-4）,organic carbon（OC） and elemental carbon（EC） were major aerosol components during the dust storm episodes,and their concentrations were higher than non-dust storm days. In addition,dust storm caused increases in NO3^-,SO4^2-and enrichment of secondary organic carbon（SOC） concentration relative to OC,suggesting that chemical reaction processes involving gas-particle conversion occurred during the long-distance transport of aerosol particles.