Document Type

Article

Publication Date

9-2016

Publication Title

Atmospheric Chemistry and Physics

ISSN

1680-7324

Volume

16

Issue

18

DOI

http://dx.doi.org/10.5194/acp-16-11823-2016

Abstract

The multiphase chemistry of glyoxal is a source of secondary organic aerosol (SOA), including its light-absorbing product imidazole-2-carboxaldehyde (IC). IC is a photosensitizer that can contribute to additional aerosol ageing and growth when its excited triplet state oxidizes hydrocarbons (reactive uptake) via H-transfer chemistry. We have conducted a series of photochemical coated-wall flow tube (CWFT) experiments using films of IC and citric acid (CA), an organic proxy and H donor in the condensed phase. The formation rate of gas-phase HO2 radicals (PHO2) was measured indirectly by converting gas-phase NO into NO2. We report on experiments that relied on measurements of NO2 formation, NO loss and HONO formation. PHO2 was found to be a linear function of (1) the [IC]×[CA] concentration product and (2) the photon actinic flux. Additionally, (3) a more complex function of relative humidity (25%

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AUTHORS

L. González Palacios (Department of Chemistry and Biochemistry, 215 UCB, University of Colorado, Boulder, CO 80309, USA) L. González Palacios (Cooperative Institute for Research in Environmental Sciences (CIRES), 216 UCB, University of Colorado, Boulder, CO 80309, USA) P. Corral Arroyo (Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland) P. Corral Arroyo (Department of Chemistry and Biochemistry, University of Bern, 2012 Bern, Switzerland) K. Z. Aregahegn (Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, 69626 Villeurbanne, France) K. Z. Aregahegn (now at: Chemistry Department, University of California, Irvine, California, 92697-202, USA) S. S. Steimer (Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland) S. S. Steimer (Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology Zurich, 8092 Zurich, Switzerland) S. S. Steimer (now at: Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK) T. Bartels-Rausch (Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland) B. Nozière (Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, 69626 Villeurbanne, France) C. George (Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, 69626 Villeurbanne, France) M. Ammann (Laboratory of Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland) R. Volkamer (Department of Chemistry and Biochemistry, 215 UCB, University of Colorado, Boulder, CO 80309, USA) R. Volkamer (Cooperative Institute for Research in Environmental Sciences (CIRES), 216 UCB, University of Colorado, Boulder, CO 80309, USA)

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