Secondary organic aerosol formation from anthropogenic air pollution: Rapid and higher than expected

Authors

  • Rainer Volkamer,

    1. Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
    2. Now at Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA.
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  • Jose L. Jimenez,

    1. Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
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  • Federico San Martini,

    1. Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
    2. Now at National Academy of Sciences, Washington, D. C., USA.
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  • Katja Dzepina,

    1. Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
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  • Qi Zhang,

    1. Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
    2. Now at Atmospheric Science Research Center, State University of New York at Albany, Albany, New York, USA.
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  • Dara Salcedo,

    1. Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
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  • Luisa T. Molina,

    1. Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
    2. Now at MCE2, La Jolla, California, USA.
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  • Douglas R. Worsnop,

    1. Aerodyne Research, Billerica, Massachusetts, USA
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  • Mario J. Molina

    1. Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
    2. Now at Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA.
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Abstract

[1] The atmospheric chemistry of volatile organic compounds (VOCs) in urban areas results in the formation of ‘photochemical smog’, including secondary organic aerosol (SOA). State-of-the-art SOA models parameterize the results of simulation chamber experiments that bracket the conditions found in the polluted urban atmosphere. Here we show that in the real urban atmosphere reactive anthropogenic VOCs (AVOCs) produce much larger amounts of SOA than these models predict, even shortly after sunrise. Contrary to current belief, a significant fraction of the excess SOA is formed from first-generation AVOC oxidation products. Global models deem AVOCs a very minor contributor to SOA compared to biogenic VOCs (BVOCs). If our results are extrapolated to other urban areas, AVOCs could be responsible for additional 3–25 Tg yr−1 SOA production globally, and cause up to −0.1 W m−2 additional top-of-the-atmosphere radiative cooling.

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