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Traffic, transport, and vegetation drive VOC concentrations in a major urban area in Texas

Shrestha, Sujan and Yoon, Subin and Erickson, Matthew H. and Guo, Fangzhou and Mehra, Manisha and Bui, Alexander A. T. and Schulze, Benjamin C. and Kotsakis, Alexander and Daube, Conner and Herndon, Scott C. and Yacovitch, Tara I. and Alvarez, Sergio and Flynn, James H. and Griffin, Robert J. and Cobb, George P. and Usenko, Sascha and Sheesley, Rebecca J. (2022) Traffic, transport, and vegetation drive VOC concentrations in a major urban area in Texas. Science of the Total Environment, 838 . Art. No. 155861. ISSN 0048-9697. doi:10.1016/j.scitotenv.2022.155861.

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The population of Texas has increased rapidly in the past decade. The San Antonio Field Study (SAFS) was designed to investigate ozone (O₃) production and precursors in this rapidly changing, sprawling metropolitan area. There are still many questions regarding the sources and chemistry of volatile organic compounds (VOCs) in urban areas like San Antonio which are affected by a complex mixture of industry, traffic, biogenic sources and transported pollutants. The goal of the SAFS campaign in May 2017 was to measure inorganic trace gases, VOCs, methane (CH₄), and ethane (C₂H₆). The SAFS field design included two sites to better assess air quality across the metro area: an urban site (Traveler's World; TW) and a downwind/suburban site (University of Texas at San Antonio; UTSA). The results indicated that acetone (2.52 ± 1.17 and 2.39 ± 1.27 ppbv), acetaldehyde (1.45 ± 1.02 and 0.93 ± 0.45 ppbv) and isoprene (0.64 ± 0.49 and 1.21 ± 0.85 ppbv; TW and UTSA, respectively) were the VOCs with the highest concentrations. Additionally, positive matrix factorization showed three dominant factors of VOC emissions: biogenic, aged urban mixed source, and acetone. Methyl vinyl ketone and methacrolein (MVK + MACR) exhibited contributions from both secondary photooxidation of isoprene and direct emissions from traffic. The C₂H₆:CH₄ demonstrated potential influence of oil and gas activities in San Antonio. Moreover, the high O₃ days during the campaign were in the NOₓ-limited O₃ formation regime and were preceded by evening peaks in select VOCs, NOₓ and CO. Overall, quantification of the concentration and trends of VOCs and trace gases in a major city in Texas offers vital information for general air quality management and supports strategies for reducing O₃ pollution. The SAFS campaign VOC results will also add to the growing body of literature on urban sources and concentrations of VOCs in major urban areas.

Item Type:Article
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URLURL TypeDescription Information;jsessionid=049cd200e3ab71ec4b0bbc974211?persistentId=doi%3A10.18738%2FT8%2FNPTA0X&version=DRAFTRelated ItemData
Shrestha, Sujan0000-0002-1676-5222
Yoon, Subin0000-0003-0821-0857
Erickson, Matthew H.0000-0001-8461-1324
Guo, Fangzhou0000-0003-3854-038X
Mehra, Manisha0000-0003-2953-7453
Bui, Alexander A. T.0000-0002-1205-1564
Schulze, Benjamin C.0000-0002-6405-8872
Daube, Conner0000-0001-8296-0272
Herndon, Scott C.0000-0002-7348-8225
Yacovitch, Tara I.0000-0002-9604-116X
Griffin, Robert J.0000-0001-7682-8769
Cobb, George P.0000-0001-8675-1283
Usenko, Sascha0000-0003-3303-2909
Sheesley, Rebecca J.0000-0002-8187-0571
Additional Information:© 2022 Elsevier. Received 4 January 2022, Revised 6 May 2022, Accepted 7 May 2022, Available online 12 May 2022, Version of Record 24 May 2022. The preparation of this work was financed through a contract from the State of Texas through the Texas Commission on Environmental Quality (PGA Number: 582-17-71581-12 and 582-18-82485-03). 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 gratefully acknowledge the NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT transport and dispersion model and/or READY website ( used in this publication. Research data for this article. The data used in this study can be accessed through the publicly available link: CRediT authorship contribution statement: S.S., S.Y., M.E., F.G., A.B., B.S., A.K., C.D., S.H., T.Y., S.A., J.H.F., R.J.G., S.U. and R.J.S. participated in the field campaign, including measurements and data quality assurance. S.S. performed data analysis and the source apportionment modeling. F.G. and R.J.G. performed the LaRC model analysis. G.C. provided resources. R.J.S. supervised the project and data analysis. S.S. prepared draft of the manuscript. S.S., M.M. and R.J.S. edited final version of the manuscript. All authors reviewed the manuscript and provided inputs for data analysis. 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 Quality582-17-71581-12
Texas Commission on Environmental Quality582-18-82485-03
Subject Keywords:PTR-MS; VOC; Ozone; Methane; Ethane; San Antonio
Record Number:CaltechAUTHORS:20220607-425293000
Persistent URL:
Official Citation:Sujan Shrestha, Subin Yoon, Matthew H. Erickson, Fangzhou Guo, Manisha Mehra, Alexander A.T. Bui, Benjamin C. Schulze, Alexander Kotsakis, Conner Daube, Scott C. Herndon, Tara I. Yacovitch, Sergio Alvarez, James H. Flynn, Robert J. Griffin, George P. Cobb, Sascha Usenko, Rebecca J. Sheesley, Traffic, transport, and vegetation drive VOC concentrations in a major urban area in Texas, Science of The Total Environment, Volume 838, Part 2, 2022, 155861, ISSN 0048-9697,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115056
Deposited By: George Porter
Deposited On:07 Jun 2022 22:49
Last Modified:07 Jun 2022 22:49

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