Observations of ozone, acyl peroxy nitrates, and their precursors during summer 2019 at Carlsbad Caverns National Park, New Mexico

A study at Carlsbad Caverns National Park reveals that ozone (O₃) formation is primarily driven by nitrogen oxides (NOₓ)-sensitive photochemistry, with significant contributions from oil and natural gas (O&G) emissions. During the summer of 2019, elevated O₃ levels exceeding the U.S. air quality standard were observed when winds came from the Permian Basin, a major O&G production region. The research identified that high O₃ days coincided with increased acyl peroxy nitrates, particularly peroxypropionyl nitrate (PPN), indicating dominant influence from anthropogenic volatile organic compounds (VOCs), often alkanes. Positive matrix factorization analysis attributed VOC and NOₓ contributions to primary emissions and secondary photochemical processing. The findings suggest that simultaneous reductions in NOₓ and non-methane VOC emissions from the O&G sector are necessary to effectively lower O₃ levels, with added benefits for reducing other secondary pollutants.

Pollack, I. B., Pan, D., Marsavin, A., Cope, E. J., Juncosa Calahorrano, J., Naimie, L., Benedict, K. B., Sullivan, A. P., Zhou, Y., Sive, B. C., Prenni, A. J., Schichtel, B. A., Collett, J., & Fischer, E. V. (2023). Observations of ozone, acyl peroxy nitrates, and their precursors during summer 2019 at Carlsbad Caverns National Park, New Mexico. Journal of the Air & Waste Management Association, 73(12), 951–968. https://doi.org/10.1080/10962247.2023.2271436