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Urban core-downwind differences and relationships related to ozone production in a major urban area in Texas

Guo, Fangzhou and Bui, Alexander A. T. and Schulze, Benjamin C. and Yoon, Subin and Shrestha, Sujan and Wallace, Henry W. and Sakai, Yuta and Actkinson, Blake W. and Erickson, Matthew H. and Alvarez, Sergio and Sheesley, Rebecca and Usenko, Sascha and Flynn, James and Griffin, Robert J. (2021) Urban core-downwind differences and relationships related to ozone production in a major urban area in Texas. Atmospheric Environment, 262 . Art. No. 118624. ISSN 1352-2310. doi:10.1016/j.atmosenv.2021.118624.

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San Antonio, the second-most populous city in Texas and the seventh-most populous city in the United States (US), has been designated a marginal non-attainment area by the US Environmental Protection Agency with respect to the 2015 ozone (O₃) National Ambient Air Quality Standard. While stationary air quality monitoring sites are operated in the region by the Texas Commission on Environmental Quality (TCEQ), there are limited in situ field measurements for O₃ and its precursors in the urban core. To better understand O₃ dynamics in San Antonio, a suite of meteorological and gas instruments was deployed during May 2017. We incorporate field measurements from two campaign sites and one TCEQ stationary monitoring site into a zero-dimensional O₃ model to characterize the local formation and destruction rates of O₃, hydroxyl radical (OH) reactivity of volatile organic compounds (VOCs), O₃ production efficiency, and O₃ formation regime in the urban core and directly downwind of San Antonio. Upwind/downwind differences indicate the importance of photochemical processing of VOCs with carbon-carbon double bonds. San Antonio was mostly in a nitrogen oxide (NO_X)-sensitive regime throughout the daytime during the campaign period, with O₃ formation peaking at noon in the city center and early afternoon at the downwind region. Formaldehyde (HCHO), isoprene, and alkenes dominated VOC reactivity, with alkenes and isoprene from San Antonio's core (upwind) likely contributing to the downwind formation of HCHO and enhancing its OH reactivity. However, their direct impact on downwind O₃ production was not observed. Model results suggest further strengthening NO_X emission controls to decrease O₃ formation in San Antonio.

Item Type:Article
Related URLs:
URLURL TypeDescription
Guo, Fangzhou0000-0003-3854-038X
Bui, Alexander A. T.0000-0002-1205-1564
Schulze, Benjamin C.0000-0002-6405-8872
Actkinson, Blake W.0000-0002-4180-0990
Usenko, Sascha0000-0003-3303-2909
Additional Information:© 2021 Elsevier. Received 25 March 2021, Revised 6 July 2021, Accepted 12 July 2021, Available online 15 July 2021. The preparation of this work was financed through a contract from the State of Texas through the Texas Commission on Environmental Quality. The content, findings, opinions and conclusions are the work of the authors and do not necessarily represent findings, opinions or conclusions of the TCEQ. The authors would like to acknowledge TCEQ funding, Mark Estes for TCEQ VOC data, Dr. Tara Yacovitch for ARI gaseous data used for validation of measurements, Dr. Dave Sullivan for PBL data, and Dr. Jason Schroeder for discussing the LRO_X/LNO_X ratio calculation using LaRC outputs. Author contributions. F.G., A.A.T.B., B.C.S, S.Y., S.S., H.W.W, M.H.E., S.A., R.S., S.U, and J.F performed the field campaign, including data quality assurance. F.G. performed the modeling and data analysis. F.G and Y.S. performed the HYSPLIT modeling. B.W.A. and B.C.S. provided input on modeling approaches. R.J.G. supervised the project and assisted with data analysis. F.G. and R.J.G. wrote and edited the manuscript. All authors proofread the manuscript. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funding AgencyGrant Number
Texas Commission on Environmental QualityUNSPECIFIED
Subject Keywords:Ozone production; Nitrogen oxides; VOC reactivity; San Antonio
Record Number:CaltechAUTHORS:20210908-171123900
Persistent URL:
Official Citation:Fangzhou Guo, Alexander A.T. Bui, Benjamin C. Schulze, Subin Yoon, Sujan Shrestha, Henry W. Wallace, Yuta Sakai, Blake W. Actkinson, Matthew H. Erickson, Sergio Alvarez, Rebecca Sheesley, Sascha Usenko, James Flynn, Robert J. Griffin, Urban core-downwind differences and relationships related to ozone production in a major urban area in Texas, Atmospheric Environment, Volume 262, 2021, 118624, ISSN 1352-2310,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110774
Deposited By: George Porter
Deposited On:08 Sep 2021 19:11
Last Modified:08 Sep 2021 19:12

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