北京市城区细粒子中铂族元素的污染特征和季节变化分析

Pollution Characteristics and Seasonal Trend of PGEs in PM_(2.5) of Beijing Urban Area

选取北京市城区的东直门和健德门站为采样点,选取2014年夏季,秋季,冬季为采样时间,研究北京市城区大气细粒子(PM2.5)中铂族元素(PGEs)的污染特征和季节变化。采用微波消解-电感耦合等离子体质谱仪法(ICP-MS)对Pd,Pt和Rh进行浓度的定量分析。研究结果表明,北京城区PM2.5中Pd,Pt和Rh的平均浓度分别为:134.3,8.478,8.443pg·m-3。PGEs的质量浓度在不同季节差别较大,Rh和Pd的季节变化特征一致,均为冬季>秋季>夏季,而Pt的季节变化特征则为秋季>夏季>冬季。富集因子分析间接表明装有三元催化转化器的机动车尾气是铂族元素污染的来源。相比于世界其他城市,北京市的Pd和Rh在可吸入颗粒物中的平均浓度是比较高的,而Pt则低于多数城市且比指导值低很多,暂时不会对人体造成影响;然而可以预测随着北京汽车工业的快速发展,细粒子中PGEs的含量会持续增加。

This paper selected Dongzhimen and Jiandemen as sampling points and the summer,autumn and winter in 2014 as the sampling time to study the pollution characteristics and seasonal trend of PGEs in PM2.5of Beijing urban area.The samples were treated by using microwave-assisted digestion procedures and the concentrations of PGEs were determined by ICP-MS.The results showed that the mean concentrations of Pd,Pt and Rh levels in all samples were 134.3,8.478,8.443pg·m-3,respectively.The mass concentration of PGEs in PM2.5differed among different seasons.The seasonal variation characteristics of Rh and Pd were consistent,both presented as winter>autumn>summer;while the characteristics of seasonal change of Pt were arranged as autumn>summer>winter.Enrichment factor analysis indirectly suggested that catalytic converters in automobile vehicles were the primary source of pollution of platinum group elements.Compared to other cities around the world,the concentrations of Pd and Rh in PM2.5of Beijing were higher than most of other cities,while Pt was lower.The level of Pt was lower than the guidance value,so it would not pose any health risk.However,with the rapid development of the automobile industry in Beijing,the concentration of the PGEs will continue to rise.