青岛环境空气PM10和PM2.5污染特征与来源比较

年分别在青岛设6个和2个采样点采集PM₁₀和PM_2.5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PM_2.5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PM_2.5的贡献,利用统计学方法比较PM₁₀和PM_2.5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PM_2.5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PM_2.5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PM_2.5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PM_2.5化学组分的分歧系数可见,春、秋季PM₁₀和PM_2.5化学构成存在一定差异,而冬、夏季二者的化学构成相似. 

Comparative Study on Pollution Characteristics and Source Apportionment of PM10 and PM2.5 in Qingdao

Ambient PM₁₀ samples were collected at six sites and ambient PM_2.5 samples were collected at two sites, respectively during the years 2011-2012in Qingdao. The mass concentration, inorganic elements, water solvent ions and carbon species were analyzed to identify the sources of PM₁₀ and PM_2.5. Meanwhile, the concentrations and chemical compositions of PM₁₀ and PM_2.5 were explored and compared. Source categories were identified and the contributions of primary and secondary sources of PM₁₀ and PM_2.5 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 PM_2.5 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 PM_2.5. The contributions of resuspended dust, coal combustion dust, construction and cement dust and sea salt were higher in PM₁₀ than in PM_2.5, 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 PM_2.5 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.