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Ozone chemistry in western U.S. wildfire plumes

Xu, Lu and Crounse, John D. and Vasquez, Krystal T. and Allen, Hannah and Wennberg, Paul O. and Bourgeois, Ilann and Brown, Steven S. and Campuzano-Jost, Pedro and Coggon, Matthew M. and Crawford, James H. and DiGangi, Joshua P. and Diskin, Glenn S. and Fried, Alan and Gargulinski, Emily M. and Gilman, Jessica B. and Gkatzelis, Georgios I. and Guo, Hongyu and Hair, Johnathan W. and Hall, Samuel R. and Halliday, Hannah A. and Hanisco, Thomas F. and Hannun, Reem A. and Holmes, Christopher D. and Huey, L. Gregory and Jimenez, Jose L. and Lamplugh, Aaron and Lee, Young Ro and Liao, Jin and Lindaas, Jakob and Neuman, J. Andrew and Nowak, John B. and Peischl, Jeff and Peterson, David A. and Piel, Felix and Richter, Dirk and Rickly, Pamela S. and Robinson, Michael A. and Rollins, Andrew W. and Ryerson, Thomas B. and Sekimoto, Kanako and Selimovic, Vanessa and Shingler, Taylor and Soja, Amber J. and St. Clair, Jason M. and Tanner, David J. and Ullmann, Kirk and Veres, Patrick R. and Walega, James and Warneke, Carsten and Washenfelder, Rebecca A. and Weibring, Petter and Wisthaler, Armin and Wolfe, Glenn M. and Womack, Caroline C. and Yokelson, Robert J. (2021) Ozone chemistry in western U.S. wildfire plumes. Science Advances, 7 (50). Art. No. eabl3648. ISSN 2375-2548. doi:10.1126/sciadv.abl3648.

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Wildfires are a substantial but poorly quantified source of tropospheric ozone (O₃). Here, to investigate the highly variable O₃ chemistry in wildfire plumes, we exploit the in situ chemical characterization of western wildfires during the FIREX-AQ flight campaign and show that O₃ production can be predicted as a function of experimentally constrained OH exposure, volatile organic compound (VOC) reactivity, and the fate of peroxy radicals. The O₃ chemistry exhibits rapid transition in chemical regimes. Within a few daylight hours, the O₃ formation substantially slows and is largely limited by the abundance of nitrogen oxides (NOₓ). This finding supports previous observations that O₃ formation is enhanced when VOC-rich wildfire smoke mixes into NOₓ-rich urban plumes, thereby deteriorating urban air quality. Last, we relate O₃ chemistry to the underlying fire characteristics, enabling a more accurate representation of wildfire chemistry in atmospheric models that are used to study air quality and predict climate.

Item Type:Article
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URLURL TypeDescription ItemFIREX-AQ data
Xu, Lu0000-0002-0021-9876
Crounse, John D.0000-0001-5443-729X
Vasquez, Krystal T.0000-0003-4540-4212
Allen, Hannah0000-0002-4218-5133
Wennberg, Paul O.0000-0002-6126-3854
Bourgeois, Ilann0000-0002-2875-1258
Brown, Steven S.0000-0001-7477-9078
Campuzano-Jost, Pedro0000-0003-3930-010X
Coggon, Matthew M.0000-0002-5763-1925
Crawford, James H.0000-0002-6982-0934
DiGangi, Joshua P.0000-0002-6764-8624
Diskin, Glenn S.0000-0002-3617-0269
Gargulinski, Emily M.0000-0002-3949-6627
Gilman, Jessica B.0000-0002-7899-9948
Gkatzelis, Georgios I.0000-0002-4608-3695
Guo, Hongyu0000-0003-0487-3610
Hair, Johnathan W.0000-0002-9672-1237
Hall, Samuel R.0000-0002-2060-7112
Halliday, Hannah A.0000-0001-9499-9836
Hanisco, Thomas F.0000-0001-9434-8507
Hannun, Reem A.0000-0001-5195-5307
Holmes, Christopher D.0000-0002-2727-0954
Huey, L. Gregory0000-0002-0518-7690
Jimenez, Jose L.0000-0001-6203-1847
Lindaas, Jakob0000-0003-1872-3162
Neuman, J. Andrew0000-0002-3986-1727
Nowak, John B.0000-0002-5697-9807
Peischl, Jeff0000-0002-9320-7101
Peterson, David A.0000-0002-9027-3779
Rickly, Pamela S.0000-0002-8459-869X
Robinson, Michael A.0000-0003-0977-9148
Rollins, Andrew W.0000-0002-1020-3966
Ryerson, Thomas B.0000-0003-2800-7581
Shingler, Taylor0000-0003-4596-1027
Soja, Amber J.0000-0001-8637-3040
St. Clair, Jason M.0000-0002-9367-5749
Tanner, David J.0000-0001-6445-8713
Ullmann, Kirk0000-0002-4724-9634
Veres, Patrick R.0000-0001-7539-353X
Warneke, Carsten0000-0003-3811-8496
Washenfelder, Rebecca A.0000-0002-8106-3702
Wisthaler, Armin0000-0001-5050-3018
Wolfe, Glenn M.0000-0001-6586-4043
Womack, Caroline C.0000-0002-7101-9054
Yokelson, Robert J.0000-0002-8415-6808
Additional Information:© 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). Received: 8 July 2021. Accepted: 20 October 2021. We thank P. P. Papin for providing the background picture in Fig. 1 and R. Schwantes and M. Bela for helpful discussions. A.W. acknowledges support from ASAP-FFG-BMVIT and thanks T. Mikoviny and L. Tomsche for field support. L.X., K.T.V., H.A., J.D.C., and P.O.W. acknowledge NASA grants 80NSSC18K0660 and 80NSSC21K1704. I.B., M.M.C., G.I.G., A.L., J.A.N., J.P., P.S.R., M.A.R., and C.C.W. acknowledge the NOAA Cooperative Agreement with CIRES, NA17OAR4320101. G.M.W., T.F.H., J.M.S., J. Liao, and R.A.H. acknowledge NASA Tropospheric Composition and NOAA AC4 grant NA17OAR4310004. R.J.Y. and V.S. acknowledge NOAA grant NA16OAR4310100. A.F., D.R., J.W., and P.W. acknowledge NASA grant 80NSSC18K0628. D.A.P. acknowledges NASA grant 80HQTR18T0063. S.R.H. and K.U. acknowledge NASA grant 80NSSC18K0638. A.J.S. and E.M.G. acknowledge NASA grant 80NSSC18K0685. H.G., P.C.-J., and J.L.J. acknowledge NASA grants 80NSSC18K0630 and 80NSSC19K0124. F.P. acknowledges support from the EU (#674911, IMPACT ITN). C.D.H. acknowledges NASA grant 80NSSC18K0625. Author contributions: L.X. and P.O.W. designed the research. J.H.C., C.W., and D.A.P. designed the flight plans. L.X., J.D.C., K.T.V., H.A., P.O.W., I.B., S.S.B., P.C.-J., M.M.C., J.P.D., G.S.D., A.F., J.B.G., G.I.G., H.G., J.W.H., S.R.H, H.A.H., T.F.H., R.A.H., C.D.H., L.G.H., E.M.G., J.L.J., A.L.,Y.R.L., J. Liao, J. Lindaas, J.A.N., J.B.N., J.P., F.P., D.R., P.S.R., M.A.R., A.W.R., T.B.R., K.S., V.S., T.S., A.J.S., J.M.S., D.J.T., K.U., P.R.V., J.W., C.W., R.A.W., P.W., A.W., G.M.W., and C.C.W. conducted measurements. L.X. analyzed the data. L.X., P.O.W., and J.D.C. wrote the paper. R.J.Y. provided critical context on fire chemistry. The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. FIREX-AQ data are available at
Funding AgencyGrant Number
National Oceanic and Atmospheric Administration (NOAA)NA17OAR4320101
National Oceanic and Atmospheric Administration (NOAA)NA17OAR4310004
National Oceanic and Atmospheric Administration (NOAA)NA16OAR4310100
European Research Council (ERC)674911
Issue or Number:50
Record Number:CaltechAUTHORS:20211209-456370000
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112321
Deposited By: George Porter
Deposited On:09 Dec 2021 17:53
Last Modified:09 Dec 2021 17:53

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