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Latitudinal distributions of atmospheric dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the western North Pacific : Sources and formation pathways
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| Title: | Latitudinal distributions of atmospheric dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls over the western North Pacific : Sources and formation pathways |
| Authors: | Bikkina, Srinivas Browse this author | | Kawamura, Kimitaka Browse this author →KAKEN DB | | Miyazaki, Yuzo Browse this author |
| Keywords: | diacids | | oxoacids | | alpha-dicarbonyls | | open ocean | | North Pacific | | photochemical oxidation |
| Issue Date: | 28-May-2015 |
| Publisher: | American Geophysical Union |
| Journal Title: | Journal of geophysical research-atmospheres |
| Volume: | 120 |
| Issue: | 10 |
| Start Page: | 5010 |
| End Page: | 5035 |
| Publisher DOI: | 10.1002/2014JD022235 |
| Abstract: | The present study aims to assess the molecular distributions of water-soluble dicarboxylic acids (diacids: C-2-C-12), oxocarboxylic acids (C-2-C-9), and -dicarbonyls (glyoxal and methylglyoxal) in aerosols collected over the western North Pacific (WNP) during a summer cruise (August to September 2008). The measured water-soluble organics show pronounced latitudinal distributions with higher concentrations in the region of 30 degrees N-45 degrees N (average 63ngm(-3)) than 10 degrees N-30 degrees N (18ngm(-3)). Mass fraction of oxalic acid (C-2) in total aliphatic diacids (sigma C-2-C-12) showed higher values (7210%) in lower latitude (10 degrees N-30 degrees N) than that (5616%) in higher latitude (30 degrees N-45 degrees N), suggesting a photochemical production of C-2 due to an increased insolation over the tropical WNP. A similar trend was found in other diagnostic ratios such as oxalic to succinic (C-2/C-4) and oxalic to glyoxylic acid (C-2/C-2), which further corroborate an enhanced photochemical aging over the WNP. In addition, relative abundances of oxalic acid in total diacids showed a marked increase as a function of ambient temperature, supporting their photochemical production. Constantly low concentration ratios of adipic and phthalic acids relative to azelaic acid suggest a small contribution of anthropogenic sources and an importance of oceanic sources during the study period. Significant production of C-2 through oxidation of biogenic volatile organic compounds emitted from the sea surface is also noteworthy, as inferred from the strong linear correlations among water-soluble organic carbon, methanesulphonic acid, and oxalic acid. Sea-to-air emission of unsaturated fatty acids also contributes to formation of diacids over the WNP. |
| Rights: | Copyright 2015 American Geophysical Union. | | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article |
| URI: | http://hdl.handle.net/2115/60103 |
| Appears in Collections: | 低温科学研究所 (Institute of Low Temperature Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 河村 公隆
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