Excessive ozone pollution at Carlsbad Caverns National Park in southeast New Mexico may be linked to oil and natural gas development in and around the Permian Basin, a new study has found.
Eight-hour ozone concentrations at the park often exceed the Environmental Protection Agency's health standard of 70 parts per billion in the summer, according to the study, published on Tuesday in the Journal of Geophysical Research-Atmospheres.
During the same season, the park also frequently sits downwind from the Permian Basin — massive oil and natural gas production territory, where development has increased fivefold over the past decade.
After exploring various potential sources of ozone precursors — compounds that indicate the presence or future formation of ozone — the authors found that oil and gas extraction is a major contributor.
“Our measurements confirm that activity such as drilling and natural gas flaring is a major driver of the high ozone levels we see," first author Andrey Marsavin, a PhD candidate at Colorado State University, said in a statement.
Unhealthy ozone concentrations have become a serious threat across the globe, including in U.S. West urban areas such as Colorado's Front Range, the authors noted. Ozone exposure can lead to asthma and other human health issues, while also damaging crops and ecosystems.
Ozone forms when emissions from both natural and human activities react in the atmosphere. Some such human sources include energy exploration and production systems, motor vehicles, industrial sites, solvents and coatings, personal care items, vegetation and lawn and garden equipment, the researchers noted.
Although federal laws over the past two decades have helped decrease the release of nitrogen dioxides and volatile organic compounds — both of which can lead to ozone creation — certain pockets of the U.S. West have only benefited from small declines, according to the scientists.
Some areas, they noted, have even experienced increases — circumstances they attributed to wildfires, surges in oil and gas development and production activities like flaring and fracking.
With that in mind, the researchers set out to uncover pollution sources in the area and quantify the link between extensive oil and gas drilling and high ozone levels. To do so, they took air pollution measurements in the park during the summer of 2019 and employed an air quality model.
In terms of pollutant makeup, the scientists found that the biggest offenders were nitrogen oxide emissions from high-temperature combustion operations.
After identifying that source, the scientists were able to track dispersal patterns across the region and single out Permian Basin drilling as a primary culprit, while recognizing that emissions from other basins upwind may be contributing on some days.
The researchers — led by Jeffrey Collett, a Colorado State University professor of chemical engineering — have partnered with the National Park Service on multiple air quality projects. Their findings, the professor noted, could apply to other nearby areas, such as the Guadalupe Mountains National Park in Texas.
The scientists expressed their intent to acquire more recent data and possibly begin integrating satellite observations in their methodology. They also discussed some potential solutions for mitigating the spread of ozone, including the use of electrified, grid-powered drill rigs.
“Many of the country’s largest oil and gas production basins are located near national parks" Collett said in a statement, emphasizing the fragility of those park ecosystems and the need to protect them.
"So, we are not quite done with studying ozone formation in this region as development in the Permian continues,” he added.
