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The impact of aerosol particle mixing state on the hygroscopicity of sea spray aerosol
Journal article   Open access

The impact of aerosol particle mixing state on the hygroscopicity of sea spray aerosol

Steven R Schill, Douglas B Collins, Christopher Lee, Holly S Morris, Gordon A Novak, Kimberly A Prather, Patricia K Quinn, Camille M Sultana, Alexei V Tivanski, Kathryn Zimmermann, …
ACS central science, Vol.1(3), pp.132-141
2015
DOI: 10.1021/acscentsci.5b00174
PMCID: PMC4827553
PMID: 27162963
url
https://doi.org/10.1021/acscentsci.5b00174View
Published (Version of record) Open Access

Abstract

Aerosol particles influence global climate by determining cloud droplet number concentrations, brightness, and lifetime. Primary aerosol particles, such as those produced from breaking waves in the ocean, display large particle-particle variability in chemical composition, morphology, and physical phase state, all of which affect the ability of individual particles to accommodate water and grow into cloud droplets. Despite such diversity in molecular composition, there is a paucity of methods available to assess how particle-particle variability in chemistry translates to corresponding differences in aerosol hygroscopicity. Here, an approach has been developed that allows for characterization of the distribution of aerosol hygroscopicity within a chemically complex population of atmospheric particles. This methodology, when applied to the interpretation of nascent sea spray aerosol, provides a quantitative framework for connecting results obtained using molecular mimics generated in the laboratory with chemically complex ambient aerosol. We show that nascent sea spray aerosol, generated in situ in the Atlantic Ocean, displays a broad distribution of particle hygroscopicities, indicative of a correspondingly broad distribution of particle chemical compositions. Molecular mimics of sea spray aerosol organic material were used in the laboratory to assess the volume fractions and molecular functionality required to suppress sea spray aerosol hygroscopicity to the extent indicated by field observations. We show that proper accounting for the distribution and diversity in particle hygroscopicity and composition are important to the assessment of particle impacts on clouds and global climate.

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