兰州城关区冬春季PM_(10)的化学组分和来源分析

Chemical Compositions and Sources of PM_(10) in Winter and Spring in Chengguan District of Lanzhou

为了解兰州市城关区冬春季PM10的来源,利用电感耦合等离子质谱(ICP-MS)测定了PM10中全样和水溶性Ti、V、Cr、Cd、Mn、Cu、Zn、As、Se、Sb、Pb、Ba、Mg、Al和Fe元素的浓度。研究结果表明,兰州市城关区冬春季PM10中这些全样和水溶性元素的总浓度均表现为冬季高于春季,且除部分地壳元素(Al和Mg)外,PM10中各全样和水溶性元素的浓度均为冬季高于春季,尤其是Zn和Pb等元素。冬春季PM10中水溶性Cd、Zn、Se、Mg、As和Mn等元素占其全样的比例相对较高,多以可溶状态存在,而Fe、Al、Pb、Ba、Ti和V等元素则相反。富集因子分析结果表明,兰州市城关区PM10中Cr、Cu、Zn、As、Cd、Pb、Sb和Se等元素的富集因子均大于10,主要来自人为污染,V、Mn、Ba、Ti、Mg、Fe和Al等元素的富集因子均接近1,主要来自地表土。因子分析结果表明,兰州市城关区冬春季PM10主要来自燃煤污染和地表土,分别占35.38%和46.33%,其次是燃油和工业污染等,占18.26%。综合分析可知,兰州市燃煤污染较严重,特别是冬季,在以后的大气治理中仍需加强燃煤污染的控制。

To understand the source of PM10 collected in Chengguan District of Lanzhou, Gansu Province in winter and spring, inductively coupled plasma-mass spectrometry （ICP-MS） was used to study the concentrations of whole and water soluble fraction elements including Ti, V, Cr, Cd, Mn, Cu, Zn, As, Se, Sb, Pb, Ba, Mg, Al and Fe in PM10. Results showed that total concentrations of these whole and water soluble fraction elements in PM10 show a decreasing trend through winter and spring. Except some crustal elements such as Al and Mg, the concentration of whole and water soluble fraction elements in winter PM10 is higher than those in spring PM10, especially Zn and Pb. ICP-MS analysis also demonstrated that the concentration of Cd, Zn, Se, Mg, As and Mn in soluble fraction is at a relatively high level, and was mostly in soluble state in winter, and totally different from Fe, Al, Pb, Ba, Ti and V. Enrichment factor （EF） analysis showed that Cr, Cu, Zn, As, Cd, Pb, Sb and Se have EF values higher than 10, suggesting that they are originated from anthropogenic source, while other elements have EF values around 1, indicating that they are from surface soil. Factor analysis indicated that Lanzhou airborne PM10 are mainly originated from coal combustion and crustal soil, accounting for 35.38% and 46.33% respectively, followed by fuel oil and industrial pollution, accounting for 18.26%. All these suggest that anthropogenic pollution in Lanzhou is dominated by coal combustion, especially in winter, and much attention should be paid in order to control air pollution.