open access

https://hdl.handle.net/2115/81607

Dicarboxylic acids, oxocarboxylic acids and alpha-dicarbonyls in atmospheric aerosols from Mt. Fuji, Japan: Implication for primary emission versus secondary formation

英語

Mt. Fuji

2019-06-01

Elsevier

Atmospheric research

221

58-71

Aerosol samples were collected at the summit of Mt. Fuji in July-August 2009 and analyzed for diacids and related compounds together with major ions to decipher the sources and formation process of organic aerosols in the free troposphere. Molecular distributions of diacids showed the predominance of oxalic acid (C-2) followed by succinic (C-4) and malonic (C-3) acids. The average concentration of total diacids is ten times higher in whole-day samples than night-only samples due to the uplift of planetary boundary layer in daytime, suggesting the day-time formation of diacids in the uplifted ground-level air mass along the mountain slope. A strong correlation is found between C-4 and levoglucosan in whole-day and nighttime samples. Liquid water content (LWC) shows strong correlations in nighttime with anthropogenic and biogenic secondary organic aerosol (SOA) tracers (e.g., adipic (0.90, p < 0.05) and phthalic acids (0.93, p < 0.05) and 3-methyl 2,3,4-trihydroxy-1-butene (0.95, p < 0.05), suggesting that aqueous-phase chemistry is important for the formation of water-soluble organic aerosols in the free troposphere. In whole-day samples, LWC is strongly correlated with organic carbon (r = 0.97, p < 0.05), and isoprene-SOA tracers such as methylthreitol (0.96, p < 0.05), methylerythritol (0.97, p < 0.05), 2-methylglyceric acid (0.94, p < 0.05) and glycolic acid (0.98, p < 0.05), suggesting that daytime SOAs are mainly from the oxidation of isoprene emitted from the regional forests on the foothill of Mt. Fuji. A strong correlation between LWC and glycolic acid further suggests that isoprene is the main precursor for the production of oxalic acid via glycolic acid as intermediate. This study supports the heterogeneous formation of diacids in the free troposphere.

学術雑誌論文

Accepted Manuscript

© 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

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