气候变化领域集成服务门户(CCPortal): Atmospheric evolution of molecular-weight-separated brown carbon from biomass burning

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DOI	10.5194/acp-19-7319-2019
	Atmospheric evolution of molecular-weight-separated brown carbon from biomass burning
	Wong J.P.S.; Tsagkaraki M.; Tsiodra I.; Mihalopoulos N.; Violaki K.; Kanakidou M.; Sciare J.; Nenes A.; Weber R.J.
发表日期	2019
ISSN	16807316
起始页码	7319
结束页码	7334
卷号	19 期号:11
英文摘要	Biomass burning is a major source of atmospheric brown carbon (BrC), and through its absorption of UV/VIS radiation, it can play an important role in the planetary radiative balance and atmospheric photochemistry. The considerable uncertainty of BrC impacts is associated with its poorly constrained sources, transformations, and atmospheric lifetime. Here we report laboratory experiments that examined changes in the optical properties of the water-soluble (WS) BrC fraction of laboratory-generated biomass burning particles from hardwood pyrolysis. Effects of direct UVB photolysis and OH oxidation in the aqueous phase on molecular-weight-separated BrC were studied. Results indicated that the majority of low-molecular-weight (MW) BrC (<400Da) was rapidly photobleached by both direct photolysis and OH oxidation on an atmospheric timescale of approximately 1h. High MW BrC (≥400Da) underwent initial photoenhancement up to ∼15h, followed by slow photobleaching over ∼10h. The laboratory experiments were supported by observations from ambient BrC samples that were collected during the fire seasons in Greece. These samples, containing freshly emitted to aged biomass burning aerosol, were analyzed for both water- and methanol-soluble BrC. Consistent with the laboratory experiments, high-MW BrC dominated the total light absorption at 365nm for both methanol and water-soluble fractions of ambient samples with atmospheric transport times of 1 to 68h. These ambient observations indicate that overall, biomass burning BrC across all molecular weights has an atmospheric lifetime of 15 to 28h, consistent with estimates from previous field studies - although the BrC associated with the high-MW fraction remains relatively stable and is responsible for light absorption properties of BrC throughout most of its atmospheric lifetime. For ambient samples of aged (>10h) biomass burning emissions, poor linear correlations were found between light absorptivity and levoglucosan, consistent with other studies suggesting a short atmospheric lifetime for levoglucosan. However, a much stronger correlation between light absorptivity and total hydrous sugars was observed, suggesting that they may serve as more robust tracers for aged biomass burning emissions. Overall, the results from this study suggest that robust model estimates of BrC radiative impacts require consideration of the atmospheric aging of BrC and the stability of high-MW BrC. © Author(s) 2019.
语种	英语
scopus关键词	adsorption; atmospheric chemistry; biomass burning; brown carbon; hydrolysis; hydroxyl radical; oxidation; photochemistry; radiation balance
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/144367
作者单位	School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30331, United States; Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, Heraklion, 71003, Greece; ICE-HT, Foundation for Research and Technology - Hellas, Patras, 26504, Greece; IERSD, National Observatory of Athens, Palea Penteli, 15236, Greece; Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), UMR 7294, University de Toulon, CNRS, IRD, France; Energy Environment and Water Research Center, Cyprus Institute, Nicosia, 1645, Cyprus; Laboratory of Atmospheric Processes and Their Impacts, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland
推荐引用方式 GB/T 7714	Wong J.P.S.,Tsagkaraki M.,Tsiodra I.,et al. Atmospheric evolution of molecular-weight-separated brown carbon from biomass burning[J],2019,19(11).
APA	Wong J.P.S..,Tsagkaraki M..,Tsiodra I..,Mihalopoulos N..,Violaki K..,...&Weber R.J..(2019).Atmospheric evolution of molecular-weight-separated brown carbon from biomass burning.Atmospheric Chemistry and Physics,19(11).
MLA	Wong J.P.S.,et al."Atmospheric evolution of molecular-weight-separated brown carbon from biomass burning".Atmospheric Chemistry and Physics 19.11(2019).