Relating CCN activity, volatility, and droplet growth kinetics of β-caryophyllene secondary organic aerosol

This study investigates the droplet formation characteristics of secondary organic aerosol (SOA) formed during the ozonolysis of sesquiterpene β-caryophyllene (with and without hydroxyl radicals present). Emphasis is placed on understanding the role of semi-volatile material on Cloud Condensation Nu...

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Bibliographic Details
Published in:Atmospheric chemistry and physics 2009-02, Vol.9 (3), p.795-812
Main Authors: Asa-Awuku, A., Engelhart, G. J., Lee, B. H., Pandis, S. N., Nenes, A.
Format: Article
Language:English
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Summary:This study investigates the droplet formation characteristics of secondary organic aerosol (SOA) formed during the ozonolysis of sesquiterpene β-caryophyllene (with and without hydroxyl radicals present). Emphasis is placed on understanding the role of semi-volatile material on Cloud Condensation Nucleus (CCN) activity and droplet growth kinetics. Aging of β-caryophyllene SOA significantly affects all CCN-relevant properties measured throughout the experiments. Using a thermodenuder and two CCN instruments, we find that CCN activity is a strong function of temperature (activation diameter at ~0.6% supersaturation: 100±10 nm at 20°C and 130±10 nm at 35°C), suggesting that the hygroscopic fraction of the SOA is volatile. The water-soluble organic carbon (WSOC) is extracted from the SOA and characterized with Köhler Theory Analysis (KTA); the results suggest that the WSOC is composed of low molecular weight (
ISSN:1680-7324
1680-7316
1680-7324
DOI:10.5194/acp-9-795-2009