Every Tuesday, Bryce Canyon National Park scientist Rhiannon Garrard gives the park’s atmosphere a weekly check-up.
At the air quality monitoring station on a hill above the canyon rim, she checked off her mental to-do list on a recent August afternoon. She collected a bucket that measures acids in the rain and swapped out a set of filters that capture particles from wildfires and carbon emissions.
The park has been monitoring its air quality like this for more than two decades, she said, and some troubling trends have emerged.
“Over the time that it's been here, we have seen increases in particulates,” which have caused visibility to steadily decrease over the years, Garrard said. “Just imagine what it would be if we didn't have that pollution.”
Data from the National Park Service show Bryce’s air has not been hitting its federal benchmarks for ozone, haze and nitrogen, either. Other parks, including Zion and Canyonlands, are in a similar boat.
Millions of people visit Utah’s Mighty Five national parks each year for their awe-inspiring views, like Bryce’s sea of red rock hoodoos. Those vistas are a natural resource the park wants to preserve.
“Visibility isn't just for us in this moment,” Garrard said. “It's easy to take it for granted, but we want future generations to be able to have these views.”
Bryce encourages visitors to use the park’s shuttle service to reduce vehicle emissions and offers real-time air quality updates online with a viewpoint webcam.
But no matter what Utah parks do to protect the air within their boundaries, it might not be enough, said Ulla Reeves, who directs the Clean Air Program for the National Parks Conservation Association.
“Air pollution knows no bounds,” Reeves said. “People think of our national parks as being remote and pristine and that they are untouched, but the reality is quite different.”
Pollution can travel hundreds of miles from its source and drift into natural areas, she said. A 2024 NPCA report Reeves worked on suggests 98% of U.S. national parks suffer from hazy skies and that air quality is unsatisfactory at all of Utah’s national parks, causing potential harm to people, plants and animals.
Now, the Trump administration is moving to roll back the foundation for many federal regulations aimed at lowering fossil fuel emissions and restoring air quality. The administration is also making plans to eliminate satellite sensors that track air pollution.
“It's very concerning,” said Lexi Tuddenham, executive director of the Healthy Environment Alliance of Utah. “I think it's a real call to action for our legislators to take up the mantle themselves and do something about it.”
If federal rules about emissions go away, Tuddenham said state leaders should set a backstop to limit how much pollution goes into Utah’s atmosphere.
Reeves’ biggest concern related to Utah parks is the continued use of coal-fired power plants. An NPCA analysis shows central Utah is home to three of the country’s most significant pollution sources that contribute to regional haze, including the Hunter and Huntington plants in Emery County.
“It's kind of an existential moment,” Reeves said. “If we are going to save ourselves and save species and protect the places we love, we have to be bold and do the right thing, which is to cut pollution and stop burning fossil fuels.”
Emissions coming from Salt Lake City and other urban areas pose a threat to parks, too. Reeves said a forthcoming NPCA report indicates the country’s top 12 urban pollution hotspots — a list that includes Las Vegas and Denver — contribute as much pollution as 331 coal-fired power plants.
It all adds up to a situation where visitors to Zion miss out on around 46 miles of visibility, according to the NPCA analysis. At Arches National Park, it’s 43 miles.
“When we talk about haze, it's not just about the visibility,” Tuddenham said. “That has economic effects, with implications for the communities around national parks that really rely on that income, and for the visitor experience that brings people from all over the world to see these incredible places.”
Then there’s the human health impact. Around the globe, air pollution is associated with 7 million premature deaths annually, according to the World Health Organization. A recent University of Utah study suggests air pollution’s health effects can continue through generations.
Poor air quality can have lasting impacts on park ecosystems, too.
Even though sulfur levels have declined, Garrard said, the Bryce Canyon landscape continues to feel lingering effects. The sulfur that acid rains delivered here decades ago can still hinder tree growth.
“We don't have a lot of water at Bryce,” she said. “That just makes it even more important to make sure that we don't have high levels of sulfur and nitrogen that might acidify the water.”
Plants at high altitudes are used to living in low nitrogen environments, Garrard said. So, if rains introduce more of that element, it could give invasive plants a leg up.
Sulfur, nitrogen, carbon and other acids in precipitation can also dissolve the park’s alkaline rock formations, she said, accelerating the erosion process.
Some of the tools parks use to measure the health of their air may be at risk, though.
Bryce had to stop one of its three weekly air sensor processes in 2024, Garrard said, because of a budget crunch at the National Atmospheric Deposition Program. She hopes the two remaining sensors can continue into the future, but it’s no sure thing.
“It's possible that we might see some sites close or just have diminishing data collection because of budgetary issues.”
