Glyoxal’s impact on dry ammonium salts: fast and reversible surface aerosol browning

Author(s)

David O. De Haan PhD, University of San DiegoFollow
Lelia N. Hawkins PhD, Harvey Mudd CollegeFollow
Kevin Jansen, University of Colorado, BoulderFollow
Hannah G. Welsh, Harvey Mudd CollegeFollow
Raunak Pednekar, Harvey Mudd CollegeFollow
Alexia de Loera, University of San DiegoFollow
Natalie G. Jimenez, University of San DiegoFollow
Margaret A. Tolbert PhD, University of Colorado, BoulderFollow
Mathieu Cazaunau PhD, Université Paris Est - CréteilFollow
Aline Gratien, Université Paris Est - CréteilFollow
Antonin Bergé, Université Paris Est - CréteilFollow
Edouard Pangui, Université Paris Est - CréteilFollow
Paola Formenti, Université Paris Est - CréteilFollow
Jean-François Doussin, Université Paris Est - CréteilFollow

Document Type

Article

Publication Date

7-2020

Journal Title

Atmospheric Chemistry and Physics

DOI

https://doi.org/10.5194/acp-20-9581-2020

Version

Publisher PDF: the final published version of the article, with professional formatting and typesetting

Disciplines

Atmospheric Sciences | Chemistry | Environmental Chemistry

Abstract

Alpha-dicarbonyl compounds are believed to form brown carbon in the atmosphere via reactions with ammonium sulfate (AS) in cloud droplets and aqueous aerosol particles. In this work, brown carbon formation in AS and other aerosol particles was quantified as a function of relative humidity (RH) during exposure to gas-phase glyoxal (GX) in chamber experiments. Under dry conditions (RH < 5%), solid AS, AS/glycine, and methylammonium sulfate aerosol particles brown within minutes upon exposure to GX, while sodium sulfate particles do not. When GX concentrations decline, browning goes away, demonstrating that this dry browning process is reversible. Declines in aerosol albedo are found to be a function of [GX]², and are consistent between AS and AS/glycine aerosol. Dry methylammonium sulfate aerosol browns 4´ more than dry AS aerosol, but deliquesced AS aerosol browns much less than dry AS aerosol. Optical measurements at 405, 450, and 530 nm provide an estimated Ångstrom absorbance coefficient of -16 ±4. This coefficient and the empirical relationship between GX and albedo are used to estimate an upper limit to global radiative forcing by brown carbon formed by 70 ppt GX reacting with AS (+7.6 ´10^-5 W/m²). This quantity is < 1% of the total radiative forcing by secondary brown carbon, but occurs almost entirely in the ultraviolet range.

Notes

Original publication information:

De Haan, D. O., Hawkins, L. N., Jansen, K., Welsh, H. G., Pednekar, R., de Loera, A., Jimenez, N. G., Tolbert, M. A., Cazaunau, M., Gratien, A., Bergé, A., Pangui, E., Formenti, P., and Doussin, J.-F.: Glyoxal's impact on dry ammonium salts: fast and reversible surface aerosol browning, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-20-9581-2020, 2020.

Digital USD Citation

De Haan, David O. PhD; Hawkins, Lelia N. PhD; Jansen, Kevin; Welsh, Hannah G.; Pednekar, Raunak; de Loera, Alexia; Jimenez, Natalie G.; Tolbert, Margaret A. PhD; Cazaunau, Mathieu PhD; Gratien, Aline; Bergé, Antonin; Pangui, Edouard; Formenti, Paola; and Doussin, Jean-François, "Glyoxal’s impact on dry ammonium salts: fast and reversible surface aerosol browning" (2020). Chemistry and Biochemistry: Faculty Scholarship. 37.
https://digital.sandiego.edu/chemistry_facpub/37