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Transition from high- to low-NOx control of night-time oxidation in the southeastern US
Nature Geoscience ( IF 18.3 ) Pub Date : 2017-06-26 00:00:00 , DOI: 10.1038/ngeo2976
P. M. Edwards , K. C. Aikin , W. P. Dube , J. L. Fry , J. B. Gilman , J. A. de Gouw , M. G. Graus , T. F. Hanisco , J. Holloway , G. Hübler , J. Kaiser , F. N. Keutsch , B. M. Lerner , J. A. Neuman , D. D. Parrish , J. Peischl , I. B. Pollack , A. R. Ravishankara , J. M. Roberts , T. B. Ryerson , M. Trainer , P. R. Veres , G. M. Wolfe , C. Warneke , S. S. Brown

The influence of nitrogen oxides (NOx) on daytime atmospheric oxidation cycles is well known, with clearly defined high- and low-NOx regimes. During the day, oxidation reactions—which contribute to the formation of secondary pollutants such as ozone—are proportional to NOx at low levels, and inversely proportional to NOx at high levels. Night-time oxidation of volatile organic compounds also influences secondary pollutants but lacks a similar clear definition of high- and low-NOx regimes, even though such regimes exist. Decreases in anthropogenic NOx emissions in the US and Europe coincided with increases in Asia over the last 10 to 20 years, and have altered both daytime and nocturnal oxidation cycles. Here we present measurements of chemical species in the lower atmosphere from day- and night-time research flights over the southeast US in 1999 and 2013, supplemented by atmospheric chemistry simulations. We find that night-time oxidation of biogenic volatile organic compounds (BVOC) is NOx-limited when the ratio of NOx to BVOC is below approximately 0.5, and becomes independent of NOx at higher ratios. The night-time ratio of NOx to BVOC in 2013 averaged 0.6 aloft. We suggest that night-time oxidation in the southeast US is in transition between NOx-dominated and ozone-dominated.

中文翻译:

从美国东南部夜间氧化的高NOx控制过渡到低NOx

氮氧化物的影响(NO X)上白天大气氧化循环是公知的,明确界定的高和低NO X的制度。白天,氧化反应,这有助于二次污染物如形成臭氧正比于NO X在较低水平,并且反比于NO X在高水平。挥发性有机化合物的夜间氧化也影响二次污染物,但缺乏高和的类似的明确定义的低NO X,即使存在制度,例如制度。减少人为NO X在过去的10到20年中,美国和欧洲的碳排放与亚洲的增长同时发生,并且白天和夜间的氧化周期都发生了变化。在这里,我们介绍了1999年和2013年在美国东南部进行的白天和夜间研究飞行在低层大气中对化学物质的测量,以及大气化学模拟的补充。我们发现,当NO x与BVOC的比率低于约0.5时,生物挥发性有机化合物(BVOC)的夜间氧化受到NO x的限制,并且在较高比率时变得独立于NO x。的夜间NO的比率X到BVOC在2013平均0.6高处。我们建议美国东南部的夜间氧化在NO x之间过渡占主导地位,而臭氧占主导地位。
更新日期:2017-07-05
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