Chemical Characterization of Water-Soluble Organic Acids in Size-Segregated Particles at a Suburban Site in Saitama, Japan

Autor: Linfa Bao, Kazuhiko Sakamoto
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: Asian Journal of Atmospheric Environment, Vol 3, Iss 1, Pp 42-51 (2009)
Druh dokumentu: article
ISSN: 1976-6912
2287-1160
DOI: 10.5572/ajae.2009.3.1.042
Popis: Saturated n-dicarboxylic acids (C2-C7, C9), unsaturated dicarboxylic acids (maleic, fumaric, phthalic acid), ketocarboxylic acids (pyruvic, glyoxylic acid), and dicarbonyls (glyoxal, methylglyoxal) were determined in size-segregated samples with a high-volume Andersen air sampler at a suburban site in Saitama, Japan, May 12-17 and July 24-27, 2007 and January 22-31, 2008. The seasonal average concentrations of these detected organic acids were 670 ng/m3, accounting for about 4.4-5.7% (C/C) of water-soluble organic carbon (WSOC) and 2.3-3.6% (C/C) of organic carbon (OC). The most abundant species of dicarboxylic acids was oxalic acid, followed by malonic, phthalic, or succinic acids. Glyoxylic acid and methyglyoxal were most abundant ketocarboxylic acid and dicarbonyl, respectively. Seasonal differences, size-segregated concentrations, and the correlations of these acids with ambient temperatures, oxidants, elemental carbon (EC), OC, WSOC, and ionic components were also discussed in terms of their corresponding sources and possible secondary formation pathways. The results suggested that photochemical reactions contributed more to the formation of particulate organic acids in Saitama suburban areas than did direct emissions from anthropogenic and natural sources. However, direct emissions of vehicles were also important sources of several organic acids in particles, such as phthalic and adipic acids, especially in winter.
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