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| Titel |
Chemical insights, explicit chemistry, and yields of secondary organic aerosol from OH radical oxidation of methylglyoxal and glyoxal in the aqueous phase |
| VerfasserIn |
Y. B. Lim, Y. Tan, B. J. Turpin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 17 ; Nr. 13, no. 17 (2013-09-03), S.8651-8667 |
| Datensatznummer |
250085664
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| Publikation (Nr.) |
 copernicus.org/acp-13-8651-2013.pdf |
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| Zusammenfassung |
Atmospherically abundant, volatile water-soluble organic compounds formed
through gas-phase chemistry (e.g., glyoxal (C2), methylglyoxal
(C3), and acetic acid) have great potential to form secondary organic
aerosol (SOA) via aqueous chemistry in clouds, fogs, and wet aerosols. This
paper (1) provides chemical insights into aqueous-phase OH-radical-initiated
reactions leading to SOA formation from methylglyoxal and (2) uses this and a
previously published glyoxal mechanism (Lim et al., 2010) to provide SOA
yields for use in chemical transport models. Detailed reaction mechanisms
including peroxy radical chemistry and a full kinetic model for aqueous
photochemistry of acetic acid and methylglyoxal are developed and validated
by comparing simulations with the experimental results from previous studies
(Tan et al., 2010, 2012). This new methylglyoxal model is then combined with
the previous glyoxal model (Lim et al., 2010), and is used to simulate the
profiles of products and to estimate SOA yields.
At cloud-relevant concentrations (~ 10−6 −
~ 10−3 M; Munger et al., 1995) of glyoxal and
methylglyoxal, the major photooxidation products are oxalic acid and pyruvic
acid, and simulated SOA yields (by mass) are ~ 120% for
glyoxal and ~ 80% for methylglyoxal. During droplet
evaporation oligomerization of unreacted methylglyoxal/glyoxal that did not
undergo aqueous photooxidation could enhance yields. In wet aerosols, where
total dissolved organics are present at much higher concentrations
(~ 10 M), the major oxidation products are oligomers formed
via organic radical–radical reactions, and simulated SOA yields (by mass)
are ~ 90% for both glyoxal and methylglyoxal. Non-radical
reactions (e.g., with ammonium) could enhance yields. |
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