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| Titel |
Chamber studies of SOA formation from aromatic hydrocarbons: observation of limited glyoxal uptake |
| VerfasserIn |
S. Nakao, Y. Liu, P. Tang, C.-L. Chen, J. Zhang, D. R. Cocker III |
| 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 ; 12, no. 9 ; Nr. 12, no. 9 (2012-05-03), S.3927-3937 |
| Datensatznummer |
250011111
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| Publikation (Nr.) |
 copernicus.org/acp-12-3927-2012.pdf |
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| Zusammenfassung |
| This study evaluates the significance of glyoxal acting as an intermediate
species leading to secondary organic aerosol (SOA) formation from aromatic
hydrocarbon photooxidation under humid conditions. Rapid SOA formation from
glyoxal uptake onto aqueous (NH4)2SO4 seed particles is
observed in agreement with previous studies; however, glyoxal did not
partition significantly to SOA (with or without aqueous seed) during
aromatic hydrocarbon photooxidation within an environmental chamber (RH less
than 80%). Rather, glyoxal influences SOA formation by raising hydroxyl
(OH) radical concentrations. Four experimental approaches supporting this
conclusion are presented in this paper: (1) increased SOA formation and
decreased SOA volatility in the toluene + NOx photooxidation system
with additional glyoxal was reproduced by matching OH radical concentrations
through H2O2 addition; (2) glyoxal addition to SOA seed formed from
toluene + NOx photooxidation did not increase SOA volume under dark; (3)
SOA formation from toluene + NOx photooxidation with and without
deliquesced (NH4)2SO4 seed resulted in similar SOA growth,
consistent with a minor contribution from glyoxal uptake onto deliquesced
seed and organic coatings; and (4) the fraction of a C4H9+
fragment (observed by Aerodyne High Resolution Time-of-Flight Aerosol Mass
Spectrometer, HR-ToF-AMS) in SOA from 2-tert-butylphenol (BP) oxidation was
unchanged in the presence of additional glyoxal despite enhanced SOA
formation. This study suggests that glyoxal uptake onto aerosol during the
oxidation of aromatic hydrocarbons is more limited than previously thought. |
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