Characterization of Selenium in Ambient Aerosols and Primary Emission Sources

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• 作者：Arlette De Santiago ; Amelia F. Longo ; Ellery D. Ingall ; Julia M. Diaz ; Laura E. King ; Barry Lai ; Rodney J. Weber ; Armistead G. Russell ; Michelle Oakes
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：August 19, 2014
• 年：2014
• 卷：48
• 期：16
• 页码：8988-8994
• 全文大小：328K
• ISSN：1520-5851

文摘

Atmospheric selenium (Se) in aerosols was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the oxidation state and elemental associations of Se in common primary emission sources and ambient aerosols collected from the greater Atlanta area. In the majority of ambient aerosol and primary emission source samples, the spectroscopic patterns as well as the absence of elemental correlations suggest Se is in an elemental, organic, or oxide form. XRF microscopy revealed numerous Se-rich particles, or hotspots, accounting on average for 16% of the total Se in ambient aerosols. Hotspots contained primarily Se⁰/Se(鈭扞I). However, larger, bulk spectroscopic characterizations revealed Se(IV) as the dominant oxidation state in ambient aerosol, followed by Se⁰/Se(鈭扞I) and Se(VI). Se(IV) was the only observed oxidation state in gasoline, diesel, and coal fly ash, while biomass burning contained a combination of Se⁰/Se(鈭扞I) and Se(IV). Although the majority of Se in aerosols was in the most toxic form, the Se concentration is well below the California Environmental Protection Agency chronic exposure limit (20000 ng/m³).