Dicarboxylic acids, oxoacids, benzoic acid, α-dicarbonyls, WSOC, OC, and ions in spring aerosols from Okinawa Island in the western North Pacific Rim: size distributions and formation processes
Item
Title (Dublin Core)
Dicarboxylic acids, oxoacids, benzoic acid, α-dicarbonyls, WSOC, OC, and ions in spring aerosols from Okinawa Island in the western North Pacific Rim: size distributions and formation processes
Description (Dublin Core)
Size-segregated aerosols (nine stages from < 0.43 to > 11.3 µm in diameter) were collected at Cape Hedo, Okinawa, in spring 2008 and analyzed for water-soluble diacids (C<sub>2</sub>–C<sub>12</sub>), <i>ω</i>-oxoacids (<i>ω</i>C<sub>2</sub>–<i>ω</i>C<sub>9</sub>), pyruvic acid, benzoic acid, and <i>α</i>-dicarbonyls (C<sub>2</sub>–C<sub>3</sub>) as well as water-soluble organic carbon (WSOC), organic carbon (OC), and major ions (Na<sup>+</sup>, NH<sub>4</sub><sup>+</sup>, K<sup>+</sup>, Mg<sup>2+</sup>, Ca<sup>2+</sup>, Cl<sup>−</sup>, NO<sub>3</sub><sup>−</sup>, SO<sub>4</sub><sup>2−</sup>, and MSA<sup>−</sup>). In all the size-segregated aerosols, oxalic acid (C<sub>2</sub>) was found to be the most abundant species, followed by malonic and succinic acids, whereas glyoxylic acid (<i>ω</i>C<sub>2</sub>) was the dominant oxoacid and glyoxal (Gly) was more abundant than methylglyoxal. Diacids (C<sub>2</sub>–C<sub>5</sub>), <i>ω</i>C<sub>2</sub>, and Gly as well as WSOC and OC peaked at fine mode (0.65–1.1 µm) whereas azelaic (C<sub>9</sub>) and 9-oxononanoic (<i>ω</i>C<sub>9</sub>) acids peaked at coarse mode (3.3–4.7 µm). Sulfate and ammonium were enriched in fine mode, whereas sodium and chloride were in coarse mode. Strong correlations of C<sub>2</sub>–C<sub>5</sub> diacids, <i>ω</i>C<sub>2</sub> and Gly with sulfate were observed in fine mode (<i>r</i> = 0.86–0.99), indicating a commonality in their secondary formation. Their significant correlations with liquid water content in fine mode (<i>r</i> = 0.82–0.95) further suggest an importance of the aqueous-phase production in Okinawa aerosols. They may also have been directly emitted from biomass burning in fine mode as supported by strong correlations with potassium (<i>r</i> = 0.85–0.96), which is a tracer of biomass burning. Bimodal size distributions of longer-chain diacid (C<sub>9</sub>) and oxoacid (<i>ω</i>C<sub>9</sub>) with a major peak in the coarse mode suggest that they were emitted from the sea surface microlayers and/or produced by heterogeneous oxidation of biogenic unsaturated fatty acids on sea salt particles.
Creator (Dublin Core)
Deshmukh, Dhananjay K.
Kawamura, Kimitaka
Lazaar, Manuel
Kunwar, Bhagawati
Boreddy, Suresh K. R.
Date (Dublin Core)
2018-09-18
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-16-5263-2016
https://acp.copernicus.org/articles/16/5263/2016/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
