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DOI | 10.5194/acp-20-3333-2020 |
Importance of isomerization reactions for OH radical regeneration from the photo-oxidation of isoprene investigated in the atmospheric simulation chamber SAPHIR | |
Novelli, Anna1; Vereecken, Luc1; Bohn, Birger1; Dorn, Hans-Peter1; Gkatzelis, Georgios I.1,2,3; Hofzumahaus, Andreas1; Holland, Frank1; Reimer, David1; Rohrer, Franz1; Rosanka, Simon1; Taraborrelli, Domenico1; Tillmann, Ralf1; Wegener, Robert1; Yu, Zhujun1,4; Kiendler-Scharr, Astrid1; Wahner, Andreas1; Fuchs, Hendrik1 | |
2020-03-20 | |
发表期刊 | ATMOSPHERIC CHEMISTRY AND PHYSICS
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ISSN | 1680-7316 |
EISSN | 1680-7324 |
出版年 | 2020 |
卷号 | 20期号:6页码:3333-3355 |
文章类型 | Article |
语种 | 英语 |
国家 | Germany; USA; Peoples R China |
英文摘要 | Theoretical, laboratory, and chamber studies have shown fast regeneration of the hydroxyl radical (OH) in the photochemistry of isoprene, largely due to unimolecular reactions which were previously thought not to be important under atmospheric conditions. Based on early field measurements, nearly complete regeneration was hypothesized for a wide range of tropospheric conditions, including areas such as the rainforest where slow regeneration of OH radicals is expected due to low concentrations of nitric oxide (NO). In this work the OH regeneration in isoprene oxidation is directly quantified for the first time through experiments covering a wide range of atmospherically relevant NO levels (between 0.15 and 2 ppbv - parts per billion by volume) in the atmospheric simulation chamber SAPHIR. These conditions cover remote areas partially influenced by anthropogenic NO emissions, giving a regeneration efficiency of OH close to 1, and areas like the Amazonian rainforest with very low NO, resulting in a surprisingly high regeneration efficiency of 0.5, i.e. a factor of 2 to 3 higher than explainable in the absence of unimolecular reactions. The measured radical concentrations were compared to model calculations, and the best agreement was observed when at least 50 % of the total loss of isoprene peroxy radicals conformers (weighted by their abundance) occurs via isomerization reactions for NO lower than 0.2 ppbv. For these levels of NO, up to 50 % of the OH radicals are regenerated from the products of the 1,6 alpha-hydroxy-hydrogen shift (1,6-H shift) of Z-delta-RO2 radicals through the photolysis of an unsaturated hydroperoxy aldehyde (HPALD) and/or through the fast aldehydic hydrogen shift (rate constant similar to 10 s(-1) at 300 K) in di-hydroperoxy carbonyl peroxy radicals (di-HPCARP-RO2), depending on their relative yield. The agreement between all measured and modelled trace gases (hydroxyl, hydroperoxy, and organic peroxy radicals, carbon monoxide, and the sum of methyl vinyl ketone, methacrolein, and hydroxyl hydroperoxides) is nearly independent of the adopted yield of HPALD and di-HPCARP-RO2 as both degrade relatively fast (< 1 h), forming the OH radical and CO among other products. Taking into consideration this and earlier isoprene studies, considerable uncertainties remain on the distribution of oxygenated products, which affect radical levels and organic aerosol down-wind of unpolluted isoprene-dominated regions. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000521593900003 |
WOS关键词 | LASER-INDUCED FLUORESCENCE ; GAS-PHASE REACTIONS ; PEARL RIVER DELTA ; NORTH CHINA PLAIN ; PHOTOLYSIS FREQUENCIES ; DEGRADATION SCHEME ; ORGANIC-COMPOUNDS ; RATE CONSTANTS ; RO2 RADICALS ; MEGAN MODEL |
WOS类目 | Environmental Sciences ; Meteorology & Atmospheric Sciences |
WOS研究方向 | Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/278698 |
专题 | 地球科学 |
作者单位 | 1.Forschungszentrum Julich, Inst Energy & Climate Res, Troposphere IEK-8, D-52425 Julich, Germany; 2.NOAA, Earth Syst Res Lab, Boulder, CO 80305 USA; 3.Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA; 4.Jinan Univ, Inst Mass Spectrometry & Atmospher Environm, Guangzhou 510632, Peoples R China |
推荐引用方式 GB/T 7714 | Novelli, Anna,Vereecken, Luc,Bohn, Birger,et al. Importance of isomerization reactions for OH radical regeneration from the photo-oxidation of isoprene investigated in the atmospheric simulation chamber SAPHIR[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2020,20(6):3333-3355. |
APA | Novelli, Anna.,Vereecken, Luc.,Bohn, Birger.,Dorn, Hans-Peter.,Gkatzelis, Georgios I..,...&Fuchs, Hendrik.(2020).Importance of isomerization reactions for OH radical regeneration from the photo-oxidation of isoprene investigated in the atmospheric simulation chamber SAPHIR.ATMOSPHERIC CHEMISTRY AND PHYSICS,20(6),3333-3355. |
MLA | Novelli, Anna,et al."Importance of isomerization reactions for OH radical regeneration from the photo-oxidation of isoprene investigated in the atmospheric simulation chamber SAPHIR".ATMOSPHERIC CHEMISTRY AND PHYSICS 20.6(2020):3333-3355. |
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