沈阳冬季灰霾日大气颗粒物元素粒径分布特征

Elemental Size Distribution Characteristics of Atmospheric Particles on Hazy Days during Winter in Shenyang

为分析沈阳市冬季灰霾日大气颗粒物元素粒径分布特征,2009年1月14日─2月2日,用安德森分级撞击式采样器进行大气颗粒物分级采样,并用电感耦合等离子体质谱仪(ICP-MS)对各级样品中Na和K等30余种元素进行分析,讨论了灰霾日、非霾日及除夕日大气颗粒物元素质量浓度和富集因子的粒径分布特征及来源.结果表明:灰霾日大气颗粒物及其元素的质量浓度均高于非霾日,粒径越细,质量浓度越高,越容易富集污染元素.Fe类元素以地壳元素为主,其质量浓度的粒径分布在非霾日呈双峰型,最高峰值出现在9.0～10μm粗粒径段;该类元素的粒径分布在灰霾日和除夕日呈三峰型,质量浓度的最高峰值也在9.0～10μm粗粒径段.Mn类元素在非霾日的质量浓度分布与Fe类元素相似,也呈双峰型,最高峰值出现在9.0～10μm粗粒径段;但其在灰霾日和除夕日呈双峰型,最高峰值却出现在粒径<1.1μm的细粒径段.K类和Zn类元素的质量浓度和富集因子的粒径分布均呈单峰型,峰值出现在粒径<1.1μm的细粒径段.K类元素主要来源于烟花爆竹释放;Zn类元素主要源于人为污染,Pb和As等污染元素因其来源不同,在灰霾日和非霾日的表现也不相同.

We analyzed elemental size distribution characteristics of atmospheric particles on hazy days during winter in Shenyang.The analysis was based on ICP-MS elemental analysis for over 30 types of elements including Na and K in different diameter atmospheric particles collected from 14 January to 2 February 2009 using an Anderson grading hit-type sampler.We discussed the elemental mass concentrations and particle size distribution characteristics of the enrichment factors on hazy days,normal days and Chinese New Year＇s Eve.The results showed that the mass concentrations of atmospheric particles and elements on hazy days were higher than those on normal days.The smaller the particles were the larger the difference between hazy days and normal days.The Fe-type elements were mainly earth elements.Their particle size distributions of concentration showed bimodal types on normal days,with the highest peak in the coarse particle（9.0-10 μm） section.On hazy days and Chinese New Year＇s Eve,a triple-peak distribution was observied,also with the highest peak in the coarse particle（9.0-10 μm） section.The particle size distribution of the Mn-type elements showed the same characteristics with that of the Fe-type elements on normal days,but a bimodal type with a peak in the fine particle（ 1.1 μm） section on hazy days and Chinese New Year＇s Eve.The size distributions of mass concentrations and enrichment factors of K and Zn-type elements showed a single peak in the fine fraction（ 1.1 μm） section.K-type elements mainly originated from the release of fireworks.Zn-type elements mainly originated from anthropogenic pollution.Pb and As elements had different displays on hazy days and normal days because of their different origin.