中文摘要：

为研究北京城区大气颗粒物中六价铬污染特征及来源,利用低流量采样器进行大气颗粒物采样,利用离子色谱分离、柱后衍生紫外的方法分析其中六价铬的浓度,优化了样品前处理方法.结果表明,采样期间北京城区大气颗粒物中六价铬浓度为200±86 pg·m^-3,晴天六价铬浓度均值为273±84 pg·m^-3;霾天其浓度均值为181±76 pg·m^-3.统计分析表明,六价铬与NOx（r=0.394）在0.05水平上显著相关,六价铬与相对湿度（r=-0.534）在0.01水平上显著相关.后向轨迹簇分析表明,来自偏南方向的气团时,六价铬浓度为181.0±83.4 pg·m^-3,而来自偏北方向气团时,六价铬浓度为226.5±83.1 pg·m^-3.

英文摘要：

In order to investigate the characteristics and source of hexavalent chromium in particulate matter in Beijing,samples were collected by Thermo Fisher impactors at the urban site. Samples was analyzed by ion chromatography using a system comprised of a post-column deriviatization module and a UV / VIS detector, and sample pretreatment method was optimized. The result showed concentration of hexavalent chromium was 200 ± 86 pg·m^-3,those were 273 ±84 pg·m^-3and 181±76 pg·m^-3on clear days and hazy days in Beijing during the sampling days. It shows that the significant positive correlation（ r = 0. 394） between hexavalent chromium and NOxat 0. 05 level,and the significant negative correlation（ r =- 0. 534） between hexavalent chromium and relative humidity at 0. 01 level. The backward air mass trajectory analysis suggested that concentration of hexavalent chromium was 181. 0 ±83. 4 pg·m^-3when the air mass came from the south,and that was226. 5 ±83. 1 pg·m^-3when the air mass came from the other directions.