2011—2012年分别在青岛设6个和2个采样点采集PM10和PM2.5样品,分析二者质量浓度及颗粒物中多种无机元素、水溶性离子和碳等组分的质量浓度,以研究PM10及PM2.5的污染特征.采用CMB-iteration模型估算法,确定一次源类及二次源类对PM10和PM2.5的贡献,利用统计学方法比较PM10和PM2.5的污染源.结果表明:青岛大气颗粒物质量浓度季节变化显著,表现为春、冬季高,夏、秋季低;Na、Mg、Al、Si、Ca和Fe元素主要富集在PM10中,SO42-、NO3-、EC和OC主要富集在PM2.5中;城市扬尘、煤烟尘、建筑水泥尘及海盐粒子等粗粒子在PM10中的分担率较PM2.5中的高,分担率分别为28.7%、17.2%、7.16%及4.47%;二次硫酸盐、二次硝酸盐、机动车尾气尘及SOC(二次有机碳)等在PM2.5中的分担率较PM10中的高,分担率分别为19.3%、8.97%、13.7%及6.07%;由PM10与PM2.5化学组分的分歧系数可见,春、秋季PM10和PM2.5化学构成存在一定差异,而冬、夏季二者的化学构成相似.
Ambient PM10 samples were collected at six sites and ambient PM2.5 samples were collected at two sites,respectively during the years 2011-2012 in Qingdao.The mass concentration,inorganic elements,water solvent ions and carbon species were analyzed to identify the sources of PM10 and PM2.5.Meanwhile,the concentrations and chemical compositions of PM10 and PM2.5 were explored and compared.Source categories were identified and the contributions of primary and secondary sources of PM10 and PM2.5 were determined using a CMB-iteration model,which could directly estimate the SOC concentrations in the ambient receptors without introducing the SOC profile.Simultaneously,statistical methods(enrichment factors and divergence coefficients) were applied to reveal the source characteristics and chemical compositions of particulate materials.The results showed that: the concentrations of PM10 and PM2.5 significantly changed in different seasons being greatest in spring and winter and lowest in summer and autumn.The enrichment factors of chemical compositions suggested that the elements,Na,Mg,Al,Si,Ca and Fe,dominated in PM10,while SO42-,NO3-,EC and OC were rich in PM2.5.The contributions of resuspended dust,coal combustion dust,construction and cement dust and sea salt were higher in PM10 than in PM2.5,with the contributions of 28.7%,17.2%,7.16% and 4.47%,respectively;while the contributions of secondary sulfate,secondary nitrate,vehicle exhaust and secondary organic carbon were higher in PM2.5 than in PM10,with contributions of 19.3%,8.97%,13.7% and 6.07%,respectively.The divergence coefficients of the chemical components of particulate matter were calculated for the samples of different seasons.The results showed that the chemical components were heterogeneous in spring and autumn and homogeneous in summer and winter.