西宁市非采暖季和采暖季PM2.5中14种金属元素特征

于2012年11月采暖季和2013年9月非采暖季,在青藏高原典型城市西宁市4个采样点采集细颗粒物(PM_(2.5))样品,共获得40个有效样品。用微波消解-ICP-MS法、原子荧光法分析了样品中14种重点防控金属。结果表明:14种重点防控金属中Ag、Tl平均质量浓度为0.10~0.50 ng/m~3,Co、Sb、Hg平均质量浓度为0.50~4.00 ng/m~3,V、Cd、Cr、Ni、Cu、As平均质量浓度为4.00~50.0 ng/m~3,Mn、Pb、Zn平均质量浓度为50.0~2 000 ng/m~3。采样期间,采暖季相比非采暖季,PM_(2.5)质量浓度有下降趋势,不同采样区金属元素浓度有增有减。富集因子分析结果表明,重点防控金属元素在非采暖季主要来源于土壤风沙扬尘、机动车尾气和工业排放,采暖季主要来源于土壤风沙扬尘、燃煤、燃油、机动车尾气和工业排放。非采暖季Zn、Ag、Cd、Hg、Tl和Pb富集因子较高,采暖季Zn、As、Ag、Cd、Sb、Hg、Tl、Pb富集因子较高,更容易受到人为源的影响。

A Preliminary Study on the Characteristics of 14 Metal Elements in PM2.5 during Non-Heating Season and Heating Season of Xining

In this study, 40 effective PM_2.5 samples were collected in the north, the east, the west and the middle district of Xining, a typical city of Qinghai-Tibetan Plateau in Nov 2012 and Sep 2013. And then 14 kinds of metal ions in PM_2.5 which was defined as key pollutants in China were analyzed by microwave-assisted digestion inductively coupled plasma(ICP-MS) and atomic fluorescence(AFS). The result showed that the average mass concentrations of Ag, Tl in PM_2.5 were from 0.10 ng/m³ to 0.50 ng/m³, Co, Sb and Hg were from 0.50 ng/m³ to 4.00 ng/m³, V, Cd, Cr, Ni, Cu and As were from 4.00 ng/m³ to 50.0 ng/m³, Mn, Pb and Zn was from 50.0 ng/m³ to 2000 ng/m³.During the sampling period, compared with the non-heating season, the PM_2.5 mass concentration showed a decreasing tendency, and the metal element concentration in different sampling area had different trend. Enrichment factor analysis showed that 14 kinds of metal ions in PM_2.5 were primary from raise dust, vehicle exhausts and industrial emissions in non-heating season, and raise dust, fire coal, fuel, vehicle exhausts and industrial emissions in heating season. The enrichment factor of Zn, Ag, Cd, Hg, Tl, Pb in non-heating season and Zn, As, Ag, Cd, Sb, Hg, Tl, Pb in heating season was higher than other elements, which was more susceptible to the impact of human sources.