大气中超痕量碲作为PM2.5污染源指纹识别元素的研究

The frequently occurring haze weather generally resulted in negative social effects in Beijing. In order to control and reduce the occurring of haze weather, it is necessary to understand the source, transportation, and transformation of pollutants in fine particles (PM2.5). One important source of PM2.5 is sulfur dioxide, nitrogen oxide and its photochemical products (sulfate and nitrate), which mainly origin from the combustion of fossil fuels (coal and oil). Selenium (Se) has been used as a tracer element for the study of SO2 and SO42- sources, transportation, and transformation in the atmosphere. However, tellurium (Te) has the potential to be a better tracer for the study of SO2 and SO42- transportation and transformation in the atmosphere from the viewpoint of physicochemical properties. Te has much fewer natural and anthropogenic emission sources than that of Se; thus Te should be less subject to interference from local sources in the study of long-distance pollutant transportation. Furthermore, Te is more chemically inert that Se; therefore, loss due to chemical thransformation is expected to be less. However, the concentration of Te in aerosol is extremely trace. Therefore, it is difficult to determine Te in aerosol using traditional techniques. As the development of mass spectrometry, inductively coupled plasma mass spectrometry (ICP-MS) yields sufficient sensitivity to allow the measurement of most trace elements in the environment. This project is to develop rapid, sensitive, and precise novel techniques to determine Te in aerosol using ICP-MS and S in aerosol using laser ablation (LA)-ICP-MS. Values of the elemental ratios (Te/S) in aerosol, coal, fly ash, soil, kerosene, petroleum, vehicle exhaust, rubber tires, and so on would be compared to see if ultratrace Te can be a tracer of S in the PM2.5. Finally, the quantitative data would be obtained to illustrate the sources and processes of S in the PM2.5 of Beijing for 3 years.

北京雾霾天气频繁发生，造成了较强的社会负面影响。治理雾霾需对其中主要污染物的来源、迁移和转化机理做深入全面的研究。雾霾中的PM2.5一个重要来源是煤和石油及其制品燃烧产生的二氧化硫（SO2）、氮氧化物（NOx）及其在大气光化学反应生成的硫酸盐和硝酸盐类。虽然硒已经被用作示踪元素研究大气中SO2和SO42-,但同为硫族的碲，自然和人为来源要远小于硒且化学性质比硒稳定，是比硒更合适的PM2.5中S的示踪元素。但碲在气溶胶中极其微量，难以通过传统的仪器进行检测。本项目拟开发快速、准确、灵敏的ICP-MS测定PM2.5中超痕量碲的新方法和LA-ICP-MS测定PM2.5中硫的新方法。通过测定大气气溶胶中Te/S的比值和不同的污染来源（煤、飞灰、土壤、煤油、汽油、汽车尾气、轮胎等）中的Te/S做比较，揭示北京PM2.5中S的主要来源，最后通过模型定量研究各污染源的具体贡献率。

北京雾霾天气频繁发生，造成了较强的社会负面影响。控制雾霾需对其中主要污染物的来源、迁移和转化机理做深入全面的研究。本项目开发快速、准确、灵敏的ICP-MS测定PM2.5中超痕量碲和硒的新方法。利用王水萃取、单色谱柱(AG1X8树脂)分离和提纯、三重四极杆电感耦合等离子质谱单质谱模式和双质谱模式测定PM2.5中超痕量碲和硒的新方法。同时开发了利用王水萃取、双色谱柱分离和提纯（AG1X8树脂和AG50W-X8树脂）、三重四极杆电感耦合等离子质谱单质谱模式和双质谱模式，测定PM2.5中超痕量碲和硒的新方法。Se可以直接穿过AG1X8树脂，再经过2mL的2 M HCl的淋洗，其回收率为102±2 %(n=2)。单柱分离时Te回收率为102±2 %(n=2)。双柱分离时，Te回收率为99.1±1.2 %(n=4)。此方法以后潜在应用如下：通过测定大气气溶胶中Te/Se的比值和不同的污染来源（煤、飞灰、土壤、煤油、汽油、汽车尾气、轮胎等）中的Te/Se做比较，揭示北京PM2.5中S的主要来源，最后通过模型定量研究各污染源的具体贡献率