Unconventional energy production from the Barnett Shale play in North Texas has grown and matured over the past two decades. The Dallas- Fort Worth (DFW) metroplex located adjacent to this large energy production region is a rapidly growing urban area with a population of over 7 million. DFW is currently designated as an ozone non-attainment area by U.S. Environmental Protection Agency (EPA). Texas Commission on Environmental Quality (TCEQ) operates several compliance-grade ambient air quality monitoring stations for ozone and its precursor gases in the DFW area. Ambient air quality data from three urban monitoring sites in North Texas, located in the cities of Dallas, Fort Worth and Denton, was acquired for the study period of 2000 through 2020. During 2000-2020, total nonmethane organic compound (TNMOC) concentrations decreased in Dallas and Fort Worth by about -1.62%/year and -0.63%/year, respectively, while an increase of +9.97%/year was noted in Denton. The increase in Denton was due to an increase in the observed n-alkane concentrations including those of ethane, propane, n-butane and isobutane. While acetylene, typically associated with traffic emissions along with the concentrations of oxides of nitrogen (NOx) showed a steady year-to-year decline at all three sites. The isopentane/n-pentane ratios suggest a higher influence from vehicular emissions in Dallas and Fort Worth, while Denton was influenced by emissions from natural gas activities. The ozone formation potential (OFP) was calculated using measured speciated TNMOC concentrations. Highly reactive volatile organic compounds (VOC) associated with urban sources (ethylene, propylene, and m/p-xylene) affected the calculated OFP in Dallas and Fort Worth, while slow-reacting n-alkanes linked to natural gas operations (ethane, propane, and butane) influenced the OFP in Denton. This study also highlighted a large disconnect between the reported annual county-wide emissions inventory trends of volatile organic compounds in contrast to the observed trend of TNMOC concentrations. Overall, oil and gas activities influenced the observed air quality in North Texas.
Professor Kuruvilla John serves as Professor and Chairman of the Department of Mechanical and Energy Engineering at the University of North Texas (UNT), Denton, Texas. He received his B. Tech degree in chemical engineering from Anna University, India. He earned his M.S. and Ph.D. degrees also in chemical engineering from the University of Iowa. He worked as a visiting scientist at IBM’s Bergen Scientific Centre in Norway and as a research associate with the State University of New York at Albany before moving to Texas in 1995. He started his academic career at Texas A&M University – Kingsville (TAMUK), where he also served as the associate dean and interim dean of the Frank H. Dotterweich College of Engineering. From 2009 until 2016 he served as the Associate Dean of Research and Graduate Studies for the College of Engineering at UNT. Prof. John’s research interests are in the area of environmental sustainability with a focus on air quality monitoring, modeling and assessment. He has an active research portfolio and has been instrumental in securing over 40 research contracts, grants and projects worth over $15 million from various industries and funding agencies including National Science Foundation, Department of Energy, and Texas Commission on Environmental Quality among others. He has served as principal investigator and project director of a National Science Foundation (NSF) funded center for research excellence in science and technology at TAMUK. He has authored over 75 peer-reviewed journal papers, reports, book chapters and conference papers. He has co-edited a book titled “The Changing Climate of South Texas 1900-2100: Problems and Prospects, Impacts and Implications”. He has contributed to the academic and research community globally by serving on several advisory boards, committees and councils. As a mentor, Prof. John has supervised 4 Ph.D., 57 M.S. students, and 13 post-doctoral researchers and scientists since 1995. Many of his former students are currently pursuing successful careers globally in the environmental arena as academics, research scientists and engineers.
