Long-range atmospheric transport of volatile monocarboxylic acids with Asian dust over a high mountain snow site, central Japan
Item
Title (Dublin Core)
Long-range atmospheric transport of volatile monocarboxylic acids with Asian dust over a high mountain snow site, central Japan
Description (Dublin Core)
To understand the long-range transport of monocarboxylic acids from the Asian continent to the Japanese islands, we collected snowpack samples from a pit sequence (depth ca. 6 m) at the Murodo-Daira snowfield near the summit of Mt. Tateyama, central Japan, in 2009 and 2011. Snow samples (<i>n</i> = 16) were analyzed for normal (C<sub>1</sub>–C<sub>10</sub>), branched chain (iC<sub>4</sub>–iC<sub>6</sub>), aromatic (benzoic and toluic acid isomers), and hydroxyl (glycolic and lactic) monocarboxylic acids, together with inorganic ions and dissolved organic carbon (DOC). Acetic acid (C<sub>2</sub>) was found to be a dominant species (average 125 ng g<sup>−1</sup>), followed by formic acid (C<sub>1</sub>) (85.7 ng g<sup>−1</sup>) and isopentanoic acid (iC<sub>5</sub>) (20.0 ng g<sup>−1</sup>). We found a strong correlation (<i>r</i> = 0.88) between formic plus acetic acids and non-sea-salt Ca<sup>2+</sup> that is a proxy of Asian dust. Contributions of total monocarboxylic acids to DOC in 2009 (21.2 ± 11.6 %) were higher than that in 2011 (3.75 ± 2.62 %), being consistent with higher intensity of Asian dust in 2009 than in 2011. Formic plus acetic acids also showed a positive correlation (<i>r</i> = 0.90) with benzoic acid that is a tracer of automobile exhaust, indicating that monocarboxylic acids and their precursors are largely emitted from anthropogenic sources in China and/or secondarily produced in the atmosphere by photochemical processing. In addition, the ratio of formic plus acetic acids to nss–Ca<sup>2+</sup> (0.27) was significantly higher than those (0.00036–0.0018) obtained for reference dust materials of Chinese loess deposits from the Tengger and Gobi deserts. This result suggests that volatile and semi-volatile organic acids are adsorbed on the alkaline dust particles during long-range atmospheric transport. Entrainment of organic acids by dusts is supported by a good correlation (<i>r</i> = 0.87) between formic plus acetic acids and pH of melt snow samples. Our study suggests that Asian alkaline dusts may be a carrier of volatile monocarboxylic acids.
Creator (Dublin Core)
Mochizuki, Tomoki
Kawamura, Kimitaka
Aoki, Kazuma
Sugimoto, Nobuo
Date (Dublin Core)
2018-09-18
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-16-14621-2016
https://acp.copernicus.org/articles/16/14621/2016/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
