Rapid dark aging of biomass burning as an overlooked source of oxidized organic aerosol.

Autor: Kodros JK; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece., Papanastasiou DK; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece., Paglione M; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece.; Institute of Atmospheric Sciences and Climate, Italian National Research Council, Bologna 40129, Italy., Masiol M; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece., Squizzato S; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece., Florou K; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece., Skyllakou K; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece., Kaltsonoudis C; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece., Nenes A; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece; athanasios.nenes@epfl.ch spyros@chemeng.upatras.gr.; School of Architecture, Civil and Environmental Engineering, Swiss Federal Institute of Technology Lausanne, Lausanne 1015, Switzerland., Pandis SN; Institute of Chemical Engineering Sciences, Foundation for Research & Technology-Hellas, Patras 26504, Greece; athanasios.nenes@epfl.ch spyros@chemeng.upatras.gr.; Department of Chemical Engineering, University of Patras, Patras 26504, Greece.
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2020 Dec 29; Vol. 117 (52), pp. 33028-33033. Date of Electronic Publication: 2020 Dec 14.
DOI: 10.1073/pnas.2010365117
Abstrakt: Oxidized organic aerosol (OOA) is a major component of ambient particulate matter, substantially impacting climate, human health, and ecosystems. OOA is readily produced in the presence of sunlight, and requires days of photooxidation to reach the levels observed in the atmosphere. High concentrations of OOA are thus expected in the summer; however, our current mechanistic understanding fails to explain elevated OOA during wintertime periods of low photochemical activity that coincide with periods of intense biomass burning. As a result, atmospheric models underpredict OOA concentrations by a factor of 3 to 5. Here we show that fresh emissions from biomass burning exposed to NO 2 and O 3 (precursors to the NO 3 radical) rapidly form OOA in the laboratory over a few hours and without any sunlight. The extent of oxidation is sensitive to relative humidity. The resulting OOA chemical composition is consistent with the observed OOA in field studies in major urban areas. Additionally, this dark chemical processing leads to significant enhancements in secondary nitrate aerosol, of which 50 to 60% is estimated to be organic. Simulations that include this understanding of dark chemical processing show that over 70% of organic aerosol from biomass burning is substantially influenced by dark oxidation. This rapid and extensive dark oxidation elevates the importance of nocturnal chemistry and biomass burning as a global source of OOA.
Competing Interests: The authors declare no competing interest.
(Copyright © 2020 the Author(s). Published by PNAS.)
Databáze: MEDLINE
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