Carlsbad Caverns, White Sands rank among worst national parks for air quality

Mar. 25—Above ground or below, the air in a pair of New Mexico's best-known natural parks is ... well, bad, at least according to a new study.

Two of the state's most popular national parks — Carlsbad Caverns and White Sands — were listed among the 10 worst in the country for air quality out of almost 400 examined.

Ground-level ozone — the main ingredient in smog — was a pollutant measured at high levels at both of these federal parks, putting Carlsbad Caverns fifth on the list and White Sands in the 10th spot, according to a report issued by the National Parks Conservation Association, a century-old park advocacy group.

The group compiled the report using National Park Service data, collected in 2021, to determine the severity of air pollution, hazy skies and the impacts on climate and ecosystems at several hundred destinations.

The caverns' ozone pollution at times exceeded the threshold of 70 parts per billion for federal air quality standards, earning the park a "significant level of concern," the group's most dire assessment, said Ulla Reeves, the group's interim air quality program director.

That amount of ozone is "dangerous for people to breathe," Reeves said.

Ground-level ozone can impair breathing and, at high enough doses, damage the heart and lungs. Unhealthy ozone levels are of concern at national parks, where people often engage in more strenuous activities that cause them to breathe in the pollutants more intensely, the report said.

Aside from having poor air quality, Carlsbad Caverns was among the 10 worst parks for hazy skies, a blight that reduces visitors' enjoyment because it impedes their view of the natural surroundings and darkens the sky, the report said.

Carlsbad Caverns is in the heart of New Mexico's oil country, so fossil fuel emissions are the main culprit, Reeves said. White Sands could be getting air pollution drifting from the next-door military base and neighboring cities such as Las Cruces, she said.

White Sands, known for its sprawling, majestic dunes, drew almost 730,000 visitors last year. Carlsbad Caverns, which features stunning underground rock formations, attracts about 500,000 visitors a year.

Perhaps the most troublesome finding is how prevalent the air pollution problems are across the country, the report said. Nearly all of the parks surveyed showed unhealthy air, skies that are too hazy and pollution harmful to nature, the report said.

"We found that 97% of our national parks are struggling," Reeves said. "We're seeing our parks all across the country are really getting hammered by air pollution."

Cutting ozone emissions from transportation, power plants and oil fields through stricter regulation is crucial in improving air quality at parks like Carlsbad Caverns, the report said.

Ozone not only can impair people's breathing, she said, but also can be harmful to animals, plants and water.

Two years ago, the state passed the ozone precursor rule with the aim of cutting nitrogen oxide and volatile organic compounds, or VOCs, emanating from oil fields. These gases combine to form ground-level ozone.

Regulators say the rule will reduce the precursors by an estimated 260 million pounds a year. It also would cut methane, a potent greenhouse tied to ozone, by an estimated 851 million pounds yearly.

During a 2021 public hearing, a federal official told two regulatory panels deciding the ozone rule how pollutants drifted into Carlsbad Caverns from oil fields.

"I think the evidence is fairly clear that there's exceedance of the ozone standard there, and part of the solution is looking at the oil and gas emissions in that area," said John Vimont of the National Park Service's Air Resources Division.

Since the rule went into effect, state regulators have said they began cracking down on violators, though environmentalists say enforcement is still lacking.

Reeves said the precursor rule has the potential to effectively reduce ozone pollution, including at national parks.

"I hope it makes a difference for the air quality in the parks that we love," she said.