Evidence of internal mixing of African dust and biomass burning particles by individual particle analysis using electron beam techniques
Evidence of internal mixing of African dust and biomass burning particles by individual particle analysis using electron beam techniques
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DOI：
10.1029/2009jd012938
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发表时间：
2010-07
影响因子：
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通讯作者：
V. L. Hand;G. Capes;D. Vaughan;P. Formenti;J. Haywood;H. Coe
中科院分区：
文献类型：
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作者：
V. L. Hand;G. Capes;D. Vaughan;P. Formenti;J. Haywood;H. Coe
[1]在这项研究中，生物质燃烧产生的气溶胶和粉尘气溶胶之间的相互作用是感兴趣的焦点。我们已经研究了灰尘和生物质燃烧气溶胶颗粒的形态和化学成分的空气中的过滤器采样使用环境扫描电子显微镜配备了能量色散X射线分析和图像分析系统。使用这些技术，我们能够研究矿物粉尘和生物质燃烧颗粒的样品中含有大量的生物质燃烧和粉尘气溶胶，相比占主导地位的生物质燃烧气溶胶和样品占主导地位的粉尘气溶胶。在样品中划分了13种颗粒类型。在以沙尘气溶胶为主的样品中，铝硅酸盐是主要的颗粒类型。更多的颗粒被发现富含S，Na，和K的样品中占主导地位的生物质燃烧气溶胶，和颗粒在这些样品中也被发现是完全没有氯由于老化的气溶胶和大气传输过程中的化学转化。我们认为，生物质燃烧颗粒包含所有三个特征元素的内部混合物。粒子成像显示，在含有大量生物质燃烧和矿物粉尘颗粒的样品中，多达三分之一的烟尘颗粒与矿物粉尘颗粒内部混合。这种内部混合将显著改变粒子系综的光学性质和生物质燃烧引起的直接辐射强迫。
[1] In this investigation, the interaction between aerosols derived from biomass burning and dust aerosol is the focus of interest. We have examined the morphology and chemical composition of dust and biomass burning aerosol particles sampled on airborne filters using an environmental scanning electron microscope equipped with both an energy dispersive X-ray analysis and an image analysis system. Using these techniques, we were able to study both mineral dust and biomass burning particles in samples containing significant amounts of both biomass burning and dust aerosol, compared to samples dominated by biomass burning aerosol and a sample dominated by dust aerosol. Thirteen particle types were classified in the samples. Aluminosilicates were the dominant particle type in the sample dominated by dust aerosol. Many more particles were found to be rich in S, Na, and K in the sample dominated by biomass burning aerosols, and particles in these samples were also found to be completely devoid of Cl due to aging of the aerosol and chemical conversion during atmospheric transport. We suggest that biomass burning particles containing all three characteristic elements are internal mixtures. Particle imaging showed that up to a third of soot particles were internally mixed with mineral dust particles in samples containing significant numbers of both biomass burning and mineral dust particles. This internal mixing would change the optical properties of the particle ensemble and the direct radiative forcing caused by biomass burning significantly.