沈阳市冬季大气颗粒物元素浓度及富集因子的粒径分布

Wintertime size distribution of element concentrations and enrichment factors in ambient particulates in Shenyang

利用安德森分级撞击式采样器进行大气颗粒物分级采样,用电感耦合等离子体质谱仪(ICP-MS)分析其中Na～Bi等40余种元素,讨论了沈阳冬季典型霾日、非霾日和除夕日元素质量浓度和富集因子粒径分布特征及来源.结果表明:霾日大气颗粒物质量浓度高于非霾日,粒径分布相似,呈双峰型,霾日更易富集细粒子.无论在霾日、非霾日还是在除夕日,Pb,Bi,As,Zn,Tl,Ga等污染元素浓度和富集因子的粒径分布均为细粒子单峰型,峰值出现在<1.1μm,除夕日Pb和Bi等元素浓度最高,霾日Zn,As,Tl等元素最高,它们均与人类活动导致的污染密切相关.K,Sr,Ba等元素浓度和富集因子的粒径分布也呈细粒子单峰型,主要是春节期间燃放烟花爆竹所释放.La,Fe及其所代表的地壳元素浓度和富集因子分布分别呈粗粒子三峰型和细粒子单峰型,非霾日的富集因子和浓度值高于霾日或者与霾日差别不大.霾日的形成与以自然源为主的元素输入呈负相关,与人类污染的元素成正相关关系.

Based on element analysis （Na～Bi） of different diameter atmospheric particles collected from 14 January to 2 February,2009 in Shenyang,the element concentrations and particle size distribution of enrichment factors were characterized on hazy days,normal days and New Year＇s Eve.The results showed that the mass concentrations of atmospheric particles on hazy days were higher than that on normal days.They both had similar bimodal type in their particle size distribution.The size distribution of concentrations and enrichment factors of pollution elements such as Pb,Bi,Zn,Tl,Ga showed unimodal type with fine particle on hazy days,normal days and New Year＇s Eve.The peaks appeared at fine fraction range （ 1.1 μm）.The maximum contents of Pb and Bi appeared on New Year＇s Eve,and heavy metals Zn and As reach their maximum on hazy days.They all highly correlated with the pollution caused by human activities.The size distribution of concentrations and enrichment factors of K,Sr and Ba also showed unimodal type with fine particles,which was mainly originated from the release of fireworks.In comparison,La and Fe showed triple-peak type with coarse particles and unimodal type with fine particles,respectively.The mass concentrations and enrichment factors of earth elements such as La and Fe on normal days were higher than those on hazy days.The hazy day formation was negatively correlated with elements from natural sources and positively correlated with those from human activities.