Single-Particle SEM-EDX Analysis of Iron-Containing Coarse Particulate Matter in an Urban Environment: Sources and Distribution of Iron within Cleveland, Ohio

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• 作者：Andrew P. Ault ; Thomas M. Peters ; Eric J. Sawvel ; Gary S. Casuccio ; Robert D. Willis ; Gary A. Norris ; Vicki H. Grassian
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：April 17, 2012
• 年：2012
• 卷：46
• 期：8
• 页码：4331-4339
• 全文大小：542K
• 年卷期：v.46,no.8(April 17, 2012)
• ISSN：1520-5851

文摘

The physicochemical properties of coarse-mode, iron-containing particles and their temporal and spatial distributions are poorly understood. Single-particle analysis combining X-ray elemental mapping and computer-controlled scanning electron microscopy (CCSEM-EDX) of passively collected particles was used to investigate the physicochemical properties of iron-containing particles in Cleveland, OH, in summer 2008 (Aug鈥揝ept), summer 2009 (July鈥揂ug), and winter 2010 (Feb鈥揗arch). The most abundant classes of iron-containing particles were iron oxide fly ash, mineral dust, NaCl-containing agglomerates (likely from road salt), and Ca鈥揝 containing agglomerates (likely from slag, a byproduct of steel production, or gypsum in road salt). The mass concentrations of anthropogenic fly ash particles were highest in the Flats region (downtown) and decreased with distance away from this region. The concentrations of fly ash in the Flats region were consistent with interannual changes in steel production. These particles were observed to be highly spherical in the Flats region, but less so after transport away from downtown. This change in morphology may be attributed to atmospheric processing. Overall, this work demonstrates that the method of passive collection with single-particle analysis by electron microscopy is a powerful tool to study spatial and temporal gradients in components of coarse particles. These gradients may correlate with human health effects associated with exposure to coarse-mode particulate matter.