Glyoxal's impact on dry ammonium salts: fast and reversible surface aerosol browning
| Autor: | D. O. De Haan, L. N. Hawkins, K. Jansen, H. G. Welsh, R. Pednekar, A. de Loera, N. G. Jimenez, M. A. Tolbert, M. Cazaunau, A. Gratien, A. Bergé, E. Pangui, P. Formenti, J.-F. Doussin |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Atmospheric Chemistry and Physics, Vol 20, Pp 9581-9590 (2020) |
| Druh dokumentu: | article |
| ISSN: | 1680-7316 1680-7324 |
| DOI: | 10.5194/acp-20-9581-2020 |
| Popis: | 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 2 and are consistent between AS and AS–glycine aerosol. Dry methylammonium sulfate aerosol browns 4 times 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 m−2). This quantity is |
| Databáze: | Directory of Open Access Journals |
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