河南省典型城市PM2.5无机元素污染特征及来源分析

分析2012年采暖季和非采暖季郑州市、洛阳市和平顶山市大气细颗粒物(PM_(2.5))样品中22种无机元素含量和污染特征,采用富集因子法、因子分析法研究当地PM_(2.5)中无机元素来源。结果表明:3个城市PM_(2.5)中无机元素总量在采暖季均高于非采暖季,不同季节占PM_(2.5)质量浓度的比例为1.7%~3.6%。Al、Na、Ca等地壳元素在PM_(2.5)中占比与PM_(2.5)浓度呈负相关关系,而Zn、Pb、Cu等人为源元素的占比随PM_(2.5)浓度增加无明显下降趋势。3个城市PM_(2.5)中Se、Cd、Br的富集因子高于1 000,Pb、Zn、Cu的富集因子为100~1 000,Co、Sc、Cr、Ni、As、Mn、Ba的富集因子为10~100,说明这些元素主要来源于人为源。13种人为源元素质量浓度在22种元素中占比为18.9%~26.3%,K、Fe、Ca、Al等4种元素占比为67.9%~76.1%。因子分析结果表明:3个城市无机元素来源组成有很大相似性,主要来源于燃煤、机动车、扬尘和建筑尘等,但Ni、Co、Sr、Ba还有来自其他排放源的贡献。

Characteristics and Sources Analysis of Inorganic Elements in PM2.5 in Typical Cities of Henan Province

In this study, samples were collected during heating and non-heating period in 2012 in Zhengzhou, Luoyang and Pingdingshan to explore the concentrations and characteristics of 22 inorganic elements in PM_2.5. The methods of enrichment factor and factor analysis were used to analyze the sources. Results revealed that concentrations of inorganic elements in 3 cities were higher in heating period than non-heating period. The proportions of 22 inorganic elements in PM_2.5 ranged from 1.7% to 3.6% in different sampling periods. For Al, Na and Ca, their relative mass ratios in PM_2.5 were negatively correlated with PM_2.5 concentration. However, there were no significant decreasing trends between PM_2.5 concentration and relative mass ratios of anthropogenic elements, including Zn, Pb and Cu. Among the 22 inorganic elements, Se, Cd and Br had enrichment factors above 1000 in all 3 cities while Pb, Zn and Cu had enrichment factors between 100 and 1000. The enrichment factors of Co, Sc, Cr, Ni, As, Mn and Ba were between 10 and 100. These mass concentrations of 13 anthropogenic elements amounted for 18.9% to 26.3% of 22 inorganic elements while the mass concentrations of K, Fe, Ca and Al amounted for 67.9% to 76.1%. Results of factor analysis showed that the inorganic elements of PM_2.5 in 3 cities had similar sources, mainly come from coal combustion, vehicle, fugitive dust and construction dust. But certain other sources may contribute to accumulation of Ni, Co, Sr and Ba in PM_2.5.