Spencer, K. M. and McCabe, D. C. and Crounse, J. D. and Olson, J. R. and Crawford, J. H. and Weinheimer, A. J. and Knapp, D. J. and Montzka, D. D. and Cantrell, C. A. and Hornbrook, R. S. and Mauldin, R. L. and Wennberg, P. O. (2009) Inferring ozone production in an urban atmosphere using measurements of peroxynitric acid. Atmospheric Chemistry and Physics, 9 (11). pp. 3697-3707. ISSN 1680-7316 http://resolver.caltech.edu/CaltechAUTHORS:20090826-112856142
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Observations of peroxynitric acid (HO_2NO_2) obtained simultaneously with those of NO and NO_2 provide a sensitive measure of the ozone photochemical production rate. We illustrate this technique for constraining the ozone production rate with observations obtained from the NCAR C-130 aircraft platform during the Megacity Initiative: Local and Global Research Observations (MILAGRO) intensive in Mexico during the spring of 2006. Sensitive and selective measurements of HO_2NO_2 were made in situ using chemical ionization mass spectrometry (CIMS). Observations were compared to modeled HO_2NO_2 concentrations obtained from the NASA Langley highly-constrained photochemical time-dependent box model. The median observed-to-calculated ratio of HO_2NO_2 is 1.18. At NOx levels greater than 15 ppbv, the photochemical box model underpredicts observations with an observed-to-calculated ratio of HO_2NO_2 of 1.57. As a result, we find that at high NO_x, the ozone production rate calculated using measured HO_2NO_2 is faster than predicted using accepted photochemistry. Inclusion of an additional HO_x source from the reaction of excited state NO_2 with H_2O or reduction in the rate constant of the reaction of OH with NO_2 improves the agreement.
|Additional Information:||© Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License. Received: 1 December 2008 – Published in Atmos. Chem. Phys. Discuss.: 28 January 2009. Revised: 28 April 2009 – Accepted: 15 May 2009 – Published: 8 June 2009. The authors wish to thank C. M. Roehl for synthesizing the peroxynitric acid for calibration. P. Weibring and A. Fried, D. R. Blake, and R. E. Shetter provided formaldehyde, whole air sample, and solar actinic flux measurements, respectively, which provided constrains for the photochemical box model. The authors also wish to thank the C-130 crew and support team. The HO2NO2 measurements and their interpretation was made possible with the financial support of NASA (NAG: NNG06GB32B). J. D. C. acknowledges support from the EPA-STAR Fellowship Program (FP916334012). This work has not been formally reviewed by the EPA. The views expressed in this document are solely those of the authors and the EPA does not endorse any products or commercial services mentioned in this publication.|
|Official Citation:||Spencer, K. M., McCabe, D. C., Crounse, J. D., Olson, J. R., Crawford, J. H., Weinheimer, A. J., Knapp, D. J., Montzka, D. D., Cantrell, C. A., Hornbrook, R. S., Mauldin III, R. L., and Wennberg, P. O.: Inferring ozone production in an urban atmosphere using measurements of peroxynitric acid, Atmos. Chem. Phys., 9, 3697-3707, 2009. www.atmos-chem-phys.net/9/3697/2009/|
|Usage Policy:||This work is distributed under the Creative Commons Attribution 3.0 License.|
|Deposited By:||George Porter|
|Deposited On:||04 Sep 2009 18:33|
|Last Modified:||26 Dec 2012 11:15|
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