The effect of water on gas–particle partitioning of secondary organic aerosol. Part I: α-pinene/ozone system

David R. Cocker, Simon L. Clegg, Richard C. Flagan, John H. Seinfeld

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The effect of relative humidity (RH) on aerosol formation by the semi-volatile oxidation products of the a-pinene/O3 system has been comprehensively studied. Experiments were performed in the presence of ammonium sulfate (aqueous, dry), ammonium bisulfate seed (aqueous, dry), and aqueous calcium chloride seed aerosols to ascertain their effect on the partitioning of the oxidation products. The yield of organic aerosol varies little with RH, and is not affected by the presence of dry inorganic salt aerosols. Aqueous salt aerosols reduce the yield of organic aerosol compared to that under seed-free or dry seed conditions. The degree of reduction is electrolyte dependent, with aqueous ammonium sulfate leading to the largest reduction and aqueous calcium chloride the smallest. Hygroscopic growth of the organic aerosol from
Original languageEnglish
Pages (from-to)6049-6072
Number of pages24
JournalAtmospheric Environment
Issue number35
Publication statusPublished - 2001

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