Solid organic-coated ammonium sulfate particles at high relative humidity in the summertime Arctic atmosphere

Rachel M Kirpes; Ziying Lei; Matthew Fraund; Matthew J Gunsch; Nathaniel W May; Tate E Barrett; Claire E Moffett; Andrew J Schauer; Becky Alexander; Lucia M Upchurch; Swarup China; Patricia K Quinn; Ryan C Moffet; Alexander Laskin; Rebecca J Sheesley; Kerri A Pratt; Andrew P Ault

doi:10.1073/pnas.2104496119

Solid organic-coated ammonium sulfate particles at high relative humidity in the summertime Arctic atmosphere

Proc Natl Acad Sci U S A. 2022 Apr 5;119(14):e2104496119. doi: 10.1073/pnas.2104496119. Epub 2022 Mar 28.

Authors

Rachel M Kirpes¹, Ziying Lei², Matthew Fraund³, Matthew J Gunsch¹, Nathaniel W May¹, Tate E Barrett⁴, Claire E Moffett⁵, Andrew J Schauer⁶, Becky Alexander⁷, Lucia M Upchurch^{8

9}, Swarup China¹⁰, Patricia K Quinn⁹, Ryan C Moffet³, Alexander Laskin¹⁰, Rebecca J Sheesley^{4

5}, Kerri A Pratt^{1

11}, Andrew P Ault¹

Affiliations

¹ Department of Chemistry, University of Michigan, Ann Arbor, MI 48109.
² Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109.
³ Department of Chemistry, University of the Pacific, Stockton, CA 95211.
⁴ Institute of Ecological, Earth, and Environmental Sciences, Baylor University, Waco, TX 76798.
⁵ Department of Environmental Science, Baylor University, Waco, TX 76798.
⁶ Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195.
⁷ Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195.
⁸ Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, WA 98115.
⁹ Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, WA 98115.
¹⁰ Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352.
¹¹ Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109.

Abstract

SignificancePhysical and chemical properties of individual atmospheric particles determine their climate impacts. Hygroscopic inorganic salt particles mixed with trace amounts of organic material are predicted to be liquid under typical tropospheric conditions in the summertime Arctic. Yet, we unexpectedly observed a significant concentration of solid particles composed of ammonium sulfate with an organic coating under conditions of high relative humidity and low temperature. These particle properties are consistent with marine biogenic-derived new particle formation and growth, with particle collision hypothesized to result in the solid phase. This particle source is predicted to have increasing relevance in the context of declining Arctic sea ice and increasing open water, with impacts on clouds, and therefore climate.

Keywords: Arctic aerosol; aerosol phase; atmospheric chemistry; marine biogenic aerosol; secondary aerosol.