Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance upgrade on Thursday 4th of May 2017 from 8.00am to 9.00am (BST).

During this time our websites will be offline temporarily. If you have any questions please use the feedback button on this page. We apologise for any inconvenience this might cause and thank you for your patience.


Volume 165, 2013
Previous Article Next Article

Organic aerosol formation photo-enhanced by the formation of secondary photosensitizers in aerosols

Author affiliations

Abstract

Secondary organic aerosols (SOA), which are produced by the transformations of volatile organic compounds in the atmosphere, play a central role in air quality, public health, visibility and climate, but their formation and aging remain poorly characterized. This study evidences a new mechanism for SOA formation based on photosensitized particulate-phase chemistry. Experiments were performed with a horizontal aerosol flow reactor where the diameter growth of the particles was determined as a function of various parameters. In the absence of gas-phase oxidant, experiments in which ammonium sulfate seeds containing glyoxal were exposed to gas-phase limonene and UV light exhibited a photo-induced SOA growth. Further experiments showed that this growth was due to traces of imidazole-2-carboxaldehyde (IC) in the seeds, a condensation product of glyoxal acting as an efficient photosensitizer. Over a 19 min irradiation time, 50 nm seed particles containing this compound were observed to grow between 3.5 and 30 ± 3% in the presence of either limonene, isoprene, α-pinene, β-pinene, or toluene in concentrations between 1.8 and 352 ppmv. The other condensation products of glyoxal, imidazole (IM) and 2,2-bi1H-imidazole (BI), also acted as photosensitizer but with much less efficiency under the same conditions. In the atmosphere, glyoxal and potentially other gas precursors would thus produce efficient photosensitizers in aerosol and autophotocatalyze SOA growth.

Back to tab navigation
Please wait while Download options loads

Publication details

The article was received on 20 Mar 2013, accepted on 26 Apr 2013 and first published on 26 Apr 2013


Article type: Paper
DOI: 10.1039/C3FD00044C
Citation: Faraday Discuss., 2013,165, 123-134
  •   Request permissions

    Organic aerosol formation photo-enhanced by the formation of secondary photosensitizers in aerosols

    K. Z. Aregahegn, B. Nozière and C. George, Faraday Discuss., 2013, 165, 123
    DOI: 10.1039/C3FD00044C

Search articles by author