气候变化领域集成服务门户(CCPortal): Evaluating the contribution of the unexplored photochemistry of aldehydes on the tropospheric levels of molecular hydrogen (H-2)

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DOI	10.5194/acp-22-12367-2022
	Evaluating the contribution of the unexplored photochemistry of aldehydes on the tropospheric levels of molecular hydrogen (H-2)
	Perez-Pena, Maria Paula; Fisher, Jenny A.; Millet, Dylan B.; Yashiro, Hisashi; Langenfelds, Ray L.; Krummel, Paul B.; Kable, Scott H.
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	12367
结束页码	12386
卷号	22 期号:18 页码:20
英文摘要	Molecular hydrogen, H-2, is one of the most abundant trace gases in the atmosphere. The main known chemical source of H-2 in the atmosphere is the photolysis of formaldehyde and glyoxal. Recent laboratory measurements and ground-state photochemistry calculations have shown other aldehydes photodissociate to yield H-2 as well. This aldehyde photochemistry has not been previously accounted for in atmospheric H-2 models. Here, we used two atmospheric models to test the implications of the previously unexplored aldehyde photochemistry on the H-2 tropospheric budget. We used the AtChem box model implementing the nearly chemically explicit Master Chemical Mechanism at three sites selected to represent variable atmospheric environments: London, Cabo Verde and Borneo. We conducted five box model simulations per site using varying quantum yields for the photolysis of 16 aldehydes and compared the results against a baseline. The box model simulations showed that the photolysis of acetaldehyde, propanal, methylglyoxal, glycolaldehyde and methacrolein yields the highest chemical production of H-2. We also used the GEOS-Chem 3-D atmospheric chemical transport model to test the impacts of the new photolytic H-2 source on the global scale. A new H-2 simulation capability was developed in GEOS-Chem and evaluated for 2015 and 2016. We then performed a sensitivity simulation in which the photolysis reactions of six aldehyde species were modified to include a 1 % yield of H-2. We found an increase in the chemical production of H-2 over tropical regions where high abundance of isoprene results in the secondary generation of methylglyoxal, glycolaldehyde and methacrolein, ultimately yielding H-2. We calculated a final increase of 0.4 Tg yr(-1) in the global chemical production budget, compared to a baseline production of similar to 41 Tg yr(-1). Ultimately, both models showed that H-2 production from the newly discovered photolysis of aldehydes leads to only minor changes in the atmospheric mixing ratios of H-2, at least for the aldehydes tested here when assuming a 1 % quantum yield across all wavelengths. Our results imply that the previously missing photochemical source is a less significant source of model uncertainty than other components of the H-2 budget, including emissions and soil uptake.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000855743200001
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/273325
作者单位	University of New South Wales Sydney; University of Wollongong; University of Minnesota System; University of Minnesota Twin Cities; National Institute for Environmental Studies - Japan; Commonwealth Scientific & Industrial Research Organisation (CSIRO)
推荐引用方式 GB/T 7714	Perez-Pena, Maria Paula,Fisher, Jenny A.,Millet, Dylan B.,et al. Evaluating the contribution of the unexplored photochemistry of aldehydes on the tropospheric levels of molecular hydrogen (H-2)[J],2022,22(18):20.
APA	Perez-Pena, Maria Paula.,Fisher, Jenny A..,Millet, Dylan B..,Yashiro, Hisashi.,Langenfelds, Ray L..,...&Kable, Scott H..(2022).Evaluating the contribution of the unexplored photochemistry of aldehydes on the tropospheric levels of molecular hydrogen (H-2).ATMOSPHERIC CHEMISTRY AND PHYSICS,22(18),20.
MLA	Perez-Pena, Maria Paula,et al."Evaluating the contribution of the unexplored photochemistry of aldehydes on the tropospheric levels of molecular hydrogen (H-2)".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.18(2022):20.