气候变化领域集成服务门户(CCPortal): A new model mechanism for atmospheric oxidation of isoprene: Global effects on oxidants; nitrogen oxides; organic products; and secondary organic aerosol

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DOI	10.5194/acp-19-9613-2019
	A new model mechanism for atmospheric oxidation of isoprene: Global effects on oxidants; nitrogen oxides; organic products; and secondary organic aerosol
	Bates K.H.; Jacob D.J.
发表日期	2019
ISSN	16807316
起始页码	9613
结束页码	9640
卷号	19 期号:14
英文摘要	Atmospheric oxidation of isoprene, the most abundantly emitted non-methane hydrocarbon, affects the abundances of ozone (O3), the hydroxyl radical (OH), nitrogen oxide radicals (NOx ), carbon monoxide (CO), oxygenated and nitrated organic compounds, and secondary organic aerosol (SOA).We analyze these effects in box models and in the global GEOS-Chem chemical transport model using the new reduced Caltech isoprene mechanism (RCIM) condensed from a recently developed explicit isoprene oxidation mechanism. We find many similarities with previous global models of isoprene chemistry along with a number of important differences. Proper accounting of the isomer distribution of peroxy radicals following the addition of OH and O2 to isoprene influences the subsequent distribution of products, decreasing in particular the yield of methacrolein and increasing the capacity of intramolecular hydrogen shifts to promptly regenerate OH. Hydrogen shift reactions throughout the mechanism lead to increased OH recycling, resulting in less depletion of OH under low-NO conditions than in previous mechanisms. Higher organonitrate yields and faster tertiary nitrate hydrolysis lead to more efficient NOx removal by isoprene and conversion to inorganic nitrate. Only 20% of isoprene-derived organonitrates (excluding peroxyacyl nitrates) are chemically recycled to NOx . The global yield of formaldehyde from isoprene is 22% per carbon and less sensitive to NO than in previous mechanisms. The global molar yield of glyoxal is 2 %, much lower than in previous mechanisms because of deposition and aerosol uptake of glyoxal precursors. Global production of isoprene SOA is about one-third from each of the following: Isoprene epoxydiols (IEPOX), organonitrates, and tetrafunctional compounds.We find a SOA yield from isoprene of 13% per carbon, much higher than commonly assumed in models and likely offset by SOA chemical loss. We use the results of our simulations to further condense RCIM into a mini Caltech isoprene mechanism (Mini-CIM) for less expensive implementation in atmospheric models, with a total size (108 species, 345 reactions) comparable to currently used mechanisms. © 2019 Author(s).
语种	英语
scopus关键词	aerosol; atmospheric chemistry; concentration (composition); hydroxyl radical; isoprene; nitrogen oxides; organic compound; oxidation
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/144246
作者单位	Faculty of Arts and Sciences, Harvard University, Cambridge, MA 02138, United States; School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States
推荐引用方式 GB/T 7714	Bates K.H.,Jacob D.J.. A new model mechanism for atmospheric oxidation of isoprene: Global effects on oxidants; nitrogen oxides; organic products; and secondary organic aerosol[J],2019,19(14).
APA	Bates K.H.,&Jacob D.J..(2019).A new model mechanism for atmospheric oxidation of isoprene: Global effects on oxidants; nitrogen oxides; organic products; and secondary organic aerosol.Atmospheric Chemistry and Physics,19(14).
MLA	Bates K.H.,et al."A new model mechanism for atmospheric oxidation of isoprene: Global effects on oxidants; nitrogen oxides; organic products; and secondary organic aerosol".Atmospheric Chemistry and Physics 19.14(2019).