Examining Ozone Production in the Permian Oil and Gas Basin Using Carlsbad Caverns National Park Measurements and Satellite Data

Abstract

Air pollutant emissions from oil and gas (O&G) activity in the Permian Basin of southeastern New Mexico and western Texas have substantially altered the atmospheric composition of this otherwise largely rural region. Increasing trends in summertime surface ozone (O3) are observed at sites downwind of the Permian, including Carlsbad Caverns National Park (CAVE), where >100 exceedances of the O3 National Ambient Air Quality Standard (NAAQS) have occurred since 2018. We investigate the drivers of high O3 at CAVE using summer 2021 measurements of nitrogen oxides (NOx) and volatile organic compounds (VOCs), and compare our findings with a 2019 study. VOC source apportionment using positive matrix factorization showed a dominant influence from O&G emissions during both studies, with an additional aged biomass burning smoke factor present in 2021. Observationally constrained F0AM box modeling revealed NOx-sensitive conditions at CAVE, with smoke exerting only a small effect on local O3 production but contributing approximately 10 ppbv to background O3 levels. O3 was more responsive to simulated NOx reductions than VOC reductions, though both led to O3 decreases. Observations from the Ozone Monitoring Instrument (OMI) and the TROPOspheric Monitoring Instrument (TROPOMI) show that regional nitrogen dioxide (NO2) has increased in parallel with surface O3 and without a corresponding trend in formaldehyde (HCHO), reflecting NOx-sensitive O3 production under increasing O&G-related NOx emissions. CAVE O3 exceedance days are associated with elevated TROPOMI NO2 (+8%) and HCHO (+5%) but a lower HCHO/NO2 ratio (−3%) across the Permian Basin relative to the July–August 2018–2024 mean.