Coloradans long have escaped smoggy Front Range cities by bolting to national parks and mountain wilderness — such as the Maroon Bells or the Great Sand Dunes — where, traditionally, the air and views were pristine.
Now, a gray-brown haze impairs visibility at a dozen national parks and wilderness areas in the state, federal records show. The pollution has been thickening at premier sites, such as Rocky Mountain National Park, where ozone — one component of haze — averaged 77 parts per billion this summer, above the federal health limit of 70 ppb. That’s up 18% from 65 ppb in 2019 and 11% from 69 ppb in 2015.
Colorado was supposed to submit a regional haze reduction plan to the Environmental Protection Agency by the end of last month, a requirement under the Clean Air Act. State air pollution control officials missed the deadline.
While the EPA hasn’t penalized Colorado, the feds sat in on a meeting last week where Colorado Department of Public Health and Environment officials unveiled proposed future pollution cuts by 3,986 tons per year before 2028.
“We’re absolutely committed to protecting our parks and wilderness and know that having a clean environment to live, work, and play in is critically important,” said Josh Korth, the state air pollution control technical supervisor coordinating Colorado’s compliance.
States are required by the EPA to restore air to ensure “natural visibility” — which can be 200 miles on a clear day in Rocky Mountain National Park — by 2064.
“Colorado suffers from a serious and growing regional haze crisis,” said Tracy Coppola, Colorado program manager for the National Parks and Conservation Association, a national nonprofit that advocates for protection and preservation of parks.
As the haze thickens
The main sources of haze-forming pollution are industrial facilities concentrated along Colorado’s Front Range that emit nitrogen oxides, sulfur dioxide and particulates. Climate warming-induced wildfires increasingly add particulates.
Federal agencies track air pollution in parks by measuring ozone, nitrogen, and average visibility distance.
Colorado sites where haze degrades air and visibility include the Great Sand Dunes National Park and Preserve, Rocky Mountain National Park, Mesa Verde National Park and Black Canyon of the Gunnison National Park, along with the Maroon Bells and seven other wilderness areas.
Between 2001 and 2015, federal records show impaired visibility at 156 national parks and wilderness areas nationwide – but with general improvement. In Colorado, the records over that period showed visibility improvements as follows:
- 110 miles to 120 miles in Rocky Mountain National Park
- 109 miles to 139 miles in Mesa Verde
- 104 miles to 134 miles in the Great Sand Dunes
- 123 miles to 147 miles in the Weminuche Wilderness
- 120 miles to 155 miles in the Mount Zirkel Wilderness.
But more recently, visibility in Rocky Mountain National Park has varied between 30 and 90 miles, and remained less than 50 miles this month, National Park Service records show. A park website warns “high ozone levels can have immediate health effects on park visitors,” and ozone averaged 82 ppb over eight hours this summer and spiked to 90 ppb at 7 p.m. Wednesday. In addition, nitrogen from air pollution has damaged tundra vegetation in the park.
At the Great Sand Dunes, National Park Service officials in 2018 rated the overall air quality “poor” due to impaired visibility, ozone, nitrogen and particulates.
Much of the recent haze comes from wildfires that, for compliance purposes, the EPA treats as a natural source of pollution that states are not obligated to control, Korth said.
Colorado officials believe “things are improving” in the state overall, he said.
Total annual air pollution in Colorado is estimated in state inventories at 125 million tons. And EPA officials have granted states flexibility in reducing pollution.
Colorado’s new two-part proposed haze reduction plan counts gains from shutdowns of coal-fired power plants that utilities voluntarily have scheduled by 2028. State officials calculate this would reduce haze-forming pollution by more than 30,000 tons a year, and the EPA has signed off on that.
The 3,986 tons a year of pollution reduction, which is the second part of the plan, would come from cuts at 17 facilities including power plants, cement factories, Denver International Airport and the Suncor Energy oil refinery.
Oil and gas industry facilities won’t be targeted, Korth said, because they “were not identified during the regional haze source screening activity for this planning period.”
State officials set an economic impact cost threshold of $10,000 a ton, above which companies won’t be asked to make cuts.
Will the proposed pollution reductions be enough to clear the air in parks and wilderness areas?
Korth said that’s a “great question.” And Commerce City resident Kristi Douglas, who was at the meeting, isn’t sure it’ll help.
“We’re breathing horrible air,” Douglas said. “It almost feels as if it’s too late to turn back. But, if we would enforce the strictest rules possible, maybe we’d have a chance of turning things around.”
