Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 11257-11272, 2015
https://doi.org/10.5194/acp-15-11257-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
09 Oct 2015
Observation of isoprene hydroxynitrates in the southeastern United States and implications for the fate of NOx
F. Xiong1, K. M. McAvey1, K. A. Pratt1,3, C. J. Groff1, M. A. Hostetler1, M. A. Lipton1, T. K. Starn4, J. V. Seeley5, S. B. Bertman6, A. P. Teng7, J. D. Crounse8, T. B. Nguyen8, P. O. Wennberg7,8, P. K. Misztal9, A. H. Goldstein9,10, A. B. Guenther11, A. R. Koss12,13, K. F. Olson9, J. A. de Gouw12,13, K. Baumann14, E. S. Edgerton14, P. A. Feiner15, L. Zhang15, D. O. Miller15, W. H. Brune15, and P. B. Shepson1,2 1Department of Chemistry, Purdue University, West Lafayette, IN, USA
2Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, USA
3Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
4Department of Chemistry, West Chester University of Pennsylvania, West Chester, PA, USA
5Department of Chemistry, Oakland University, Rochester, MI, USA
6Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
7Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
8Division of Geophysical and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
9Department of Environmental Science, Policy, & Management, University of California at Berkeley, Berkeley, CA, USA
10Department of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, CA, USA
11Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA
12Cooperative Institute for Research in Environmental Sciences, Boulder, CO, USA
13NOAA Earth System Research Laboratory, Boulder, CO, USA
14Atmospheric Research & Analysis, Inc., Cary, NC, USA
15Department of Meteorology, Pennsylvania State University, University Park, PA, USA
Abstract. 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.

Citation: Xiong, F., McAvey, K. M., Pratt, K. A., Groff, C. J., Hostetler, M. A., Lipton, M. A., Starn, T. K., Seeley, J. V., Bertman, S. B., Teng, A. P., Crounse, J. D., Nguyen, T. B., Wennberg, P. O., Misztal, P. K., Goldstein, A. H., Guenther, A. B., Koss, A. R., Olson, K. F., de Gouw, J. A., Baumann, K., Edgerton, E. S., Feiner, P. A., Zhang, L., Miller, D. O., Brune, W. H., and Shepson, P. B.: Observation of isoprene hydroxynitrates in the southeastern United States and implications for the fate of NOx, Atmos. Chem. Phys., 15, 11257-11272, https://doi.org/10.5194/acp-15-11257-2015, 2015.
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Short summary
Hydroxynitrates from isoprene oxidation were quantified both in the laboratory and through field studies. The yield of hydroxynitrates 9(+4/-3)% derived from chamber experiments was applied in a zero-dimensional model to simulate the production and loss of isoprene hydroxynitrates in an ambient environment during the 2013 Southern Oxidant and Aerosol Study (SOAS). NOx was determined to be the limiting factor for the formation of isoprene hydroxynitrates during SOAS.
Hydroxynitrates from isoprene oxidation were quantified both in the laboratory and through field...
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