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Effects of chemical composition and mixing state on size-resolved hygroscopicity and cloud condensation nuclei activity of submicron aerosols at a suburban site in northern Japan in summer

IR@NPL: CSIR-National Physical Laboratory, New Delhi

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Title Effects of chemical composition and mixing state on size-resolved hygroscopicity and cloud condensation nuclei activity of submicron aerosols at a suburban site in northern Japan in summer
 
Creator Mueller, Astrid
Miyazaki, Yuzo
Aggarwal, Shankar G.
Kitamori, Yasuyuki
Boreddy, Suresh K. R
Kawamura, Kimitaka
 
Subject Meteorology & Atmospheric Sciences
 
Description Ambient hygroscopic properties, numbers of size-segregated cloud condensation nuclei (CCN) at different supersaturations (0.1%-0.8%), and the chemical composition of submicron particles were simultaneously measured at a suburban site in northern Japan in summer. Two distinct periods with different growth factors (GF), CCN activation diameters, and chemical compositions were observed. The data suggest that internally mixed sulfate aerosols dominated the accumulation size mode in relatively aged aerosols during the first period, whereas particles observed during the latter periods showed external mixing dominated by organics, which was linked to low hygroscopicity and CCN activity. In particular, the higher loading of water-soluble organic matter (WSOM; similar to 60% of OM by mass) with increased WSOM/sulfate ratios corresponded to a low hygroscopicity parameter derived from the CCN measurement (kappa(CCN) = 0.15 +/- 0.02) at a dry diameter (D-dry) of 146 nm. The results suggest that WSOM, likely dominated by the influence of biogenic sources, contributed to reducing the hygroscopicity and CCN activation at this particle size. Temporal variations in the number concentrations for low GF mode at D-dry = 49.6 nm were similar to those in the elemental carbon (EC) concentration, suggesting that EC contributed to reducing hygroscopicity at this smaller size. Our results suggest that chemical composition and mixing state are important factors controlling the hygroscopicity and CCN activation of submicron particles. These results provide useful data sets of size-resolved subsaturated and supersaturated hygroscopicity and highlight the importance of the abundance of OM relative to sulfate in predicting the effects on climate change.
 
Publisher American Geophysical Union
 
Date 2017-09-16
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://npl.csircentral.net/2678/1/Effects%20of%20chemical%20composition%20.pdf
Mueller, Astrid and Miyazaki, Yuzo and Aggarwal, Shankar G. and Kitamori, Yasuyuki and Boreddy, Suresh K. R and Kawamura, Kimitaka (2017) Effects of chemical composition and mixing state on size-resolved hygroscopicity and cloud condensation nuclei activity of submicron aerosols at a suburban site in northern Japan in summer. Journal of Geophysical Research: Atmospheres, 122. pp. 9301-9318. ISSN 2169-897X
 
Relation http://npl.csircentral.net/2678/