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DOI	10.5194/acp-19-7609-2019
	Effect of temperature on the formation of highly oxygenated organic molecules (HOMs) from alpha-pinene ozonolysis
	Quelever L.L.J.; Kristensen K.; Normann Jensen L.; Rosati B.; Teiwes R.; Daellenbach K.R.; Peräkylä O.; Roldin P.; Bossi R.; Pedersen H.B.; Glasius M.; Bilde M.; Ehn M.
发表日期	2019
ISSN	16807316
起始页码	7609
结束页码	7625
卷号	19 期号:11
英文摘要	Highly oxygenated organic molecules (HOMs) are important contributors to secondary organic aerosol (SOA) and new-particle formation (NPF) in the boreal atmosphere. This newly discovered class of molecules is efficiently formed from atmospheric oxidation of biogenic volatile organic compounds (VOCs), such as monoterpenes, through a process called autoxidation. This process, in which peroxy-radical intermediates isomerize to allow addition of molecular oxygen, is expected to be highly temperature-dependent. Here, we studied the dynamics of HOM formation during α-pinene ozonolysis experiments performed at three different temperatures, 20, 0 and -15 ĝC, in the Aarhus University Research on Aerosol (AURA) chamber. We found that the HOM formation, under our experimental conditions (50 ppb α-pinene and 100 ppb ozone), decreased considerably at lower temperature, with molar yields dropping by around a factor of 50 when experiments were performed at 0 ĝC, compared to 20 ĝC. At -15 ĝC, the HOM signals were already close to the detection limit of the nitrate-based chemical ionization atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer used for measuring gas-phase HOMs. Surprisingly, comparing spectra measured at 0 and 20 ĝC, ratios between HOMs of different oxidation levels, e.g., the typical HOM products C10H14O7, C10H14O9, and C10H14O11, changed considerably less than the total HOM yields. More oxidized species have undergone more isomerization steps; yet, at lower temperature, they did not decrease more than the less oxidized species. One possible explanation is that the primary rate-limiting steps forming these HOMs occur before the products become oxygenated enough to be detected by our CI-APi-TOF (i.e., typically seven or more oxygen atoms). The strong temperature dependence of HOM formation was observed under temperatures highly relevant to the boreal forest, but the exact magnitude of this effect in the atmosphere will be much more complex: the fate of peroxy radicals is a competition between autoxidation (influenced by temperature and VOC type) and bimolecular termination pathways (influenced mainly by concentration of reaction partners). While the temperature influence is likely smaller in the boreal atmosphere than in our chamber, both the magnitude and complexity of this effect clearly deserve more consideration in future studies in order to estimate the ultimate role of HOMs on SOA and NPF under different atmospheric conditions. © 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
语种	英语
scopus关键词	aerosol; atmospheric pressure; concentration (composition); ionization; nitrate; oxidation; peroxy radical; temperature effect; volatile organic compound
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/144349
作者单位	Institute for Atmospheric and Earth System Research (INAR/Physics), University of Helsinki, P.O. Box 6400014, Finland; Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C, 8000, Denmark; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, 8000, Denmark; Division of Nuclear Physics, Lund University, P.O. Box 118, Lund, 22100, Sweden; Department of Environmental Science, Aarhus University, Frederiksborgvej 399, Roskilde, 4000, Denmark; Department of Engineering, Aarhus University, Finlandsgade 12, Aarhus N, 8200, Denmark
推荐引用方式 GB/T 7714	Quelever L.L.J.,Kristensen K.,Normann Jensen L.,et al. Effect of temperature on the formation of highly oxygenated organic molecules (HOMs) from alpha-pinene ozonolysis[J],2019,19(11).
APA	Quelever L.L.J..,Kristensen K..,Normann Jensen L..,Rosati B..,Teiwes R..,...&Ehn M..(2019).Effect of temperature on the formation of highly oxygenated organic molecules (HOMs) from alpha-pinene ozonolysis.Atmospheric Chemistry and Physics,19(11).
MLA	Quelever L.L.J.,et al."Effect of temperature on the formation of highly oxygenated organic molecules (HOMs) from alpha-pinene ozonolysis".Atmospheric Chemistry and Physics 19.11(2019).