• 关键词：有机碳  元素碳  二次有机碳  粒径分布

• 基金项目：上海市科委基础研究重点项目(No.10JC1417200)

• 曾友石
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 王广华
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 姚剑
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 李玉兰
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 黄豫
• 南华大学核科学技术学院,衡阳 421001

• 袁宁
• 南华大学核科学技术学院,衡阳 421001

• 刘邃庆
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 钱渊
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 吴胜伟
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 刘卫
• 中国科学院上海应用物理研究所-中国科学院核分析与核能技术重点实验室,上海 201800

• 摘要：利用STAPLEX六级采样器(<0.49,0.49～0.95,0.95～1.50,1.50～3.00,3.00～7.20,>7.20 μm)结合美国DRI碳分析仪分析了上海市嘉定区2008年4月至2010年10月大气颗粒物中EC和OC的含量和粒径分布,用EC示踪法估算POC和SOC的含量及粒径分布,并结合颗粒物中水溶性钾定量分析了上海市嘉定区大气颗粒物中EC和OC来自生物质燃烧排放的分担率.结果显示,上海市嘉定区大气颗粒物中EC与OC的含量分别为(3.54±1.46) μg·m^-3和(19.35±9.38) μg·m^-3,占颗粒物质量的2.8%±1.1%和14.8%±4.0%.嘉定区PM_3.0中的OC与北京、杭州和武汉等城市的夏季以及珠江三角洲和上海市市区PM_2.5中的OC相当,而EC含量偏小,反映了嘉定区EC受机动车尾气排放影响小.上海市嘉定区大气颗粒物中EC、OC、POC和SOC均呈双模态分布,其中EC、POC的分布峰位于<0.49 μm和>3.00 μm的粒径段,OC的分布峰位于<0.95 μm和>3.00 μm的粒径段,SOC的分布峰位于0.49～0.95 μm和3.0～7.2 μm的粒径段.各粒径段OC中SOC的比重分别为:36.64%±20.66%、74.92%±22.74%、54.80%±23.52%、56.30%±23.00%、66.89%±23.37%和47.22%±23.65%,说明嘉定区SOC的污染严重.基于OC、EC与K⁺的线性回归分析,大气颗粒物中生物质燃烧排放的OC和EC分担率分别为40%和32%,且各粒径段的分担率也有差别,最大的OC和EC分担率为76%和50%,对应于0.49～0.95 μm粒径段.

• Abstract：In present study the atmospheric particulate samples, which were collected from April 2008 to October 2010 at Jiading District, Shanghai using STAPLEX pumping system of a six-stage cascade impactor (size range: <0.49 μm, 0.49～0.95 μm, 0.95～1.50 μm, 1.50～3.00 μm, 3.00～7.20 μm, >7.20 μm), were completely investigated. Organic carbon (OC) and Elemental carbon (EC) of those samples were determined by DRI carbon analyzer. Annual average of EC and OC concentrations of atmospheric particulates were (3.54±1.46) μg·m^-3 and (19.35±9.38) μg·m^-3, respectively, accounting for 2.8%±1.1% and 14.8%±4.0% of TSP mass at Jiading District, Shanghai. Comparing between the PM_2.5 in the Pearl River Delta, urban Shanghai, Beijing, Hangzhou, Wuhan and PM_3.0 at Jiading District, the OC concentration was in the same level, but EC was smaller at Jiading District. It was indicated that EC was less affected by motor vehicle exhaust emissions at Jiading District. Further, primary organic carbon (POC) and second organic carbon(SOC)were estimated by setting EC as the tracer of POC. SOC accounted for 36.64%±20.66%, 74.92%±22.74%, 54.80%±23.52%, 56.30%±23.00%, 66.89%±23.37% and 47.22%±23.65% of OC in different size segments, respectively, which indicated that the pollution of SOC was serious at Jiading District. The size distribution of EC, OC, POC and SOC in atmospheric particles at Jiading District showed a bimodal distribution. The peaks of EC and POC were at <0.49 μm and >3.00 μm, while that of OC were located at <0.95 μm and >3.00 μm, and that of SOC were at 0.49～0.95 μm and 3.0～7.2 μm, respectively. Finally, biomass burning contributions to EC and to OC were quantified using water-soluble potassium of atmospheric particulates. Based on the linear regression analysis of OC, EC and K⁺, the contributions of biomass burning to OC and to EC in atmospheric particles were 40% and 32%, respectively. Those contributions showed differently at various particle sizes. Further, the largest contributions of OC and EC were 76% and 50%, respectively, corresponding to the size segment of 0.49～0.95 μm.

• Key words：organic carbon  elemental carbon  secondary organic carbon  particle size distribution

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