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DOI	10.5194/acp-20-13701-2020
	Photooxidation of pinonaldehyde at ambient conditions investigated in the atmospheric simulation chamber SAPHIR
	Rolletter M.; Blocquet M.; Kaminski M.; Bohn B.; Dorn H.-P.; Hofzumahaus A.; Holland F.; Li X.; Rohrer F.; Tillmann R.; Wegener R.; Kiendler-Scharr A.; Wahner A.; Fuchs H.
发表日期	2020
ISSN	1680-7316
起始页码	13701
结束页码	13719
卷号	20 期号:22
英文摘要	The photooxidation of pinonaldehyde, one product of the α-pinene degradation, was investigated in the atmospheric simulation chamber SAPHIR under natural sunlight at low NO concentrations (< 0:2 ppbv) with and without an added hydroxyl radical (OH) scavenger. With a scavenger, pinonaldehyde was exclusively removed by photolysis, whereas without a scavenger, the degradation was dominated by reaction with OH. In both cases, the observed rate of pinonaldehyde consumption was faster than predicted by an explicit chemical model, the Master Chemical Mechanism (MCM, version 3.3.1). In the case with an OH scavenger, the observed photolytic decay can be reproduced by the model if an experimentally determined photolysis frequency is used instead of the parameterization in the MCM. A good fit is obtained when the photolysis frequency is calculated from the measured solar actinic flux spectrum, absorption cross sections published by Hallquist et al. (1997), and an effective quantum yield of 0.9. The resulting photolysis frequency is 3.5 times faster than the parameterization in the MCM. When pinonaldehyde is mainly removed by reaction with OH, the observed OH and hydroperoxy radical (HO2) concentrations are underestimated in the model by a factor of 2. Using measured HO2 as a model constraint brings modeled and measured OH concentrations into agreement. This suggests that the chemical mechanism includes all relevant OH-producing reactions but is missing a source for HO2. The missing HO2 source strength of (0.8 to 1.5) ppbvh-1 is similar to the rate of the pinonaldehyde consumption of up to 2.5 ppbvh-1. When the model is constrained by HO2 concentrations and the experimentally derived photolysis frequency, the pinonaldehyde decay is well represented. The photolysis of pinonaldehyde yields 0.18±0.20 formaldehyde molecules at NO concentrations of less than 200 pptv, but no significant acetone formation is observed. When pinonaldehyde is also oxidized by OH under low NO conditions (maximum 80 pptv), yields of acetone and formaldehyde increase over the course of the experiment from 0.2 to 0.3 and from 0.15 to 0.45, respectively. Fantechi et al. (2002) proposed a degradation mechanism based on quantum-chemical calculations, which is considerably more complex than the MCM scheme and contains additional reaction pathways and products. Implementing these modifications results in a closure of the model-measurement discrepancy for the products acetone and formaldehyde, when pinonaldehyde is degraded only by photolysis. In contrast, the underprediction of formed acetone and formaldehyde is worsened compared to model results by the MCM, when pinonaldehyde is mainly degraded in the reaction with OH. This shows that the current mechanisms lack acetone and formaldehyde sources for low NO conditions like in these experiments. Implementing the modifications suggested by Fantechi et al. (2002) does not improve the model-measurement agreement of OH and HO2. © Author(s) 2020.
语种	英语
scopus关键词	aldehyde; ambient air; atmospheric chemistry; atmospheric modeling; computer simulation; concentration (composition); hydroxyl radical; nitrogen oxides; photooxidation
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/247371
作者单位	Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, IEK-8: Troposphere, Jülich, Germany; Ministère de l'Education Nationale et de la Jeunesse, 110 rue de Grenelle, Paris SP 07, 75357, France; Federal Office of Consumer Protection and Food Safety, Department 5: Method Standardization, Reference Laboratories, Resistance to Antibiotics, Berlin, Germany; College of Environmental Sciences and Engineering, Peking University, Beijing, China
推荐引用方式 GB/T 7714	Rolletter M.,Blocquet M.,Kaminski M.,et al. Photooxidation of pinonaldehyde at ambient conditions investigated in the atmospheric simulation chamber SAPHIR[J],2020,20(22).
APA	Rolletter M..,Blocquet M..,Kaminski M..,Bohn B..,Dorn H.-P..,...&Fuchs H..(2020).Photooxidation of pinonaldehyde at ambient conditions investigated in the atmospheric simulation chamber SAPHIR.ATMOSPHERIC CHEMISTRY AND PHYSICS,20(22).
MLA	Rolletter M.,et al."Photooxidation of pinonaldehyde at ambient conditions investigated in the atmospheric simulation chamber SAPHIR".ATMOSPHERIC CHEMISTRY AND PHYSICS 20.22(2020).