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| Titel |
Observation of isoprene hydroxynitrates in the southeastern United States and implications for the fate of NOx |
| VerfasserIn |
F. Xiong, K. M. McAvey, K. A. Pratt, C. J. Groff, M. A. Hostetler, M. A. Lipton, T. K. Starn, J. V. Seeley, S. B. Bertman, A. P. Teng, J. D. Crounse, T. B. Nguyen, P. O. Wennberg, P. K. Misztal, A. H. Goldstein, A. B. Guenther, A. R. Koss, K. F. Olson, J. A. de Gouw, K. Baumann, E. S. Edgerton, P. A. Feiner, L. Zhang, D. O. Miller, W. H. Brune, P. B. Shepson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 19 ; Nr. 15, no. 19 (2015-10-09), S.11257-11272 |
| Datensatznummer |
250120088
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| Publikation (Nr.) |
 copernicus.org/acp-15-11257-2015.pdf |
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| Zusammenfassung |
| Isoprene hydroxynitrates (IN) are tracers of the photochemical oxidation of
isoprene in high NOx environments. Production and loss of IN have a
significant influence on the NOx cycle and tropospheric O3
chemistry. To better understand IN chemistry, a series of photochemical
reaction chamber experiments was conducted to determine the IN yield from
isoprene photooxidation at high NO concentrations (> 100 ppt). By
combining experimental data and calculated isomer distributions, a total IN
yield of 9(+4/−3) % was derived. The result was applied in a
zero-dimensional model to simulate production and loss of ambient IN
observed in a temperate forest atmosphere, during the Southern Oxidant and
Aerosol Study (SOAS) field campaign, from 27 May to 11 July 2013. The 9 %
yield was consistent with the observed IN/(MVK+MACR) ratios observed
during SOAS. By comparing field observations with model simulations, we
identified NO as the limiting factor for ambient IN production during SOAS,
but vertical mixing at dawn might also contribute (~ 27 %)
to IN dynamics. A close examination of isoprene's oxidation products
indicates that its oxidation transitioned from a high-NO dominant chemical
regime in the morning into a low-NO dominant regime in the afternoon. A
significant amount of IN produced in the morning high NO regime could be
oxidized in the low NO regime, and a possible reaction scheme was proposed. |
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