title: Heterogeneous glyoxal oxidation: a potential source of secondary organic aerosol.
abstract: Laboratory studies are described that suggest reactive uptake of glyoxal on particulate containing HNO(3) could contribute to the formation of secondary organic aerosol (SOA) in the upper troposphere (UT). Using a Knudsen cell flow reactor, glyoxal is observed to react on supercooled H(2)O/HNO(3) surfaces to form condensed-phase glyoxylic acid. This product was verified by derivatization and GC-MS analysis. The reactive uptake coefficient, γ, of glyoxal varies only slightly with the pressure of nitric acid, from γ = 0.5 to 3.0 × 10(-3) for nitric acid pressures between 10(-8) and 10(-6) Torr. The data do not show any dependence on temperature (181-201 K) or pressure of glyoxal (10(-7) to 10(-5) Torr). Using the determined reactive uptake kinetics in a simple model shows that glyoxal uptake to supercooled H(2)O/HNO(3) may account for 4-53% of the total organic mass fraction of aerosol in the UT.
authors.affiliation: Cooperative Institute for Research in the Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States. connellb@colorado.edu
authors.forename: B M
authors.initials: BM
authors.lastname: Connelly
authors.forename: D O
authors.initials: DO
authors.lastname: De Haan
authors.forename: M A
authors.initials: MA
authors.lastname: Tolbert
mesh_terms: D000336:Aerosols / Q000138:chemical synthesis / Q000737:chemistry; D001272:Atmosphere / Q000737:chemistry; D006037:Glyoxal / Q000138:chemical synthesis / Q000737:chemistry*; D007700:Kinetics; D017942:Nitric Acid / Q000737:chemistry; D010084:Oxidation-Reduction; D014867:Water / Q000737:chemistry
chemical_list: D000336:Aerosols; D014867:Water; D017942:Nitric Acid; D006037:Glyoxal