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Gas-particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology

TitleGas-particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology
Publication TypeJournal Article
Year of Publication2013
AuthorsShiraiwa, M, Zuend, A, Bertram, AK, Seinfeld, JH
JournalPHYSICAL CHEMISTRY CHEMICAL PHYSICS
Volume15
Pagination11441-11453
ISSN1463-9076
Abstract

Atmospheric aerosols, comprising organic compounds and inorganic salts, play a key role in air quality and climate. Mounting evidence exists that these particles frequently exhibit phase separation into predominantly organic and aqueous electrolyte-rich phases. As well, the presence of amorphous semi-solid or glassy particle phases has been established. Using the canonical system of ammonium sulfate mixed with organics from the ozone oxidation of a-pinene, we illustrate theoretically the interplay of physical state, non-ideality, and particle morphology affecting aerosol mass concentration and the characteristic timescale of gas-particle mass transfer. Phase separation can significantly affect overall particle mass and chemical composition. Semi-solid or glassy phases can kinetically inhibit the partitioning of semivolatile components and hygroscopic growth, in contrast to the traditional assumption that organic compounds exist in quasi-instantaneous gas-particle equilibrium. These effects have significant implications for the interpretation of laboratory data and the development of improved atmospheric air quality and climate models.

DOI10.1039/c3cp51595h