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

Cocker, David R., III and Clegg, Simon L. and Flagan, Richard C. and Seinfeld, John H. (2001) The effect of water on gas–particle partitioning of secondary organic aerosol. Part I: α-pinene/ozone system. Atmospheric Environment, 35 (35). pp. 6049-6072. ISSN 1352-2310. doi:10.1016/S1352-2310(01)00404-6.

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The effect of relative humidity (RH) on aerosol formation by the semi-volatile oxidation products of the α-pinene/O_3 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 <2% to 85% RH was also monitored, and could be satisfactorily represented as the sum of the individual contributions of the organic and inorganic fractions. The implications of the growth factor measurements for concentration/activity relationships of the condensed phase organic material (assuming a liquid solution) was explored. The formation of the organic aerosol was investigated using a simple two component model, and also one including the 12 product compounds identified in a previous study. The experimental results for <2% and 50% RH (without salt seed aerosols) could be satisfactorily predicted. However, the aqueous salt seed aerosols are predicted to increase the overall yield due to the dissolution of the organic compounds into the water associated with the seed aerosol—the opposite effect to that observed. The implications of two distinct phases existing the aerosol phase were investigated.

Item Type:Article
Related URLs:
URLURL TypeDescription
Cocker, David R., III0000-0002-0586-0769
Flagan, Richard C.0000-0001-5690-770X
Seinfeld, John H.0000-0003-1344-4068
Additional Information:© 2001 Elsevier. Received 10 February 2001; accepted 29 July 2001. This work was supported by the US Environmental Protection Agency Center on Airborne Organics, US Environmental Protection Agency Agreement CR827331-01-0, and the Chevron Corporation. David Cocker was supported in part by a NSF Graduate Fellowship. The contribution of Simon Clegg was supported by an Advanced Fellowship from the Natural Environment Research Council of the UK. Special thanks to K.M. Cocker, M. Kalberer, and N.E. Whitlock.
Funding AgencyGrant Number
Environmental Protection Agency (EPA)CR827331-01-0
Chevron CorporationUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Natural Environment Research Council (NERC)UNSPECIFIED
Subject Keywords:Secondary organic aerosols; Relative humidity; Biogenic hydrocarbons
Issue or Number:35
Record Number:CaltechAUTHORS:20150806-171813438
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Official Citation:David R. Cocker III, Simon L. Clegg, Richard C. Flagan, John H. Seinfeld, The effect of water on gas–particle partitioning of secondary organic aerosol. Part I: α-pinene/ozone system, Atmospheric Environment, Volume 35, Issue 35, December 2001, Pages 6049-6072, ISSN 1352-2310, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59296
Deposited By: Irina Meininger
Deposited On:07 Aug 2015 23:46
Last Modified:10 Nov 2021 22:18

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