News Archive

July 25, 2023

Federal Court Upholds Air Quality Standards in Front Range, Denies Fossil Fuel Industry Exemption

Boulder County Commissioners Welcome Decision, Say It Will Protect Health of All Community Members

Boulder County, Colo. -- A federal appeals court has ruled in favor of the Boulder County Board of Commissioners, the Environmental Protection Agency (EPA), the Center for Biological Diversity, Sierra Club, and National Parks Conservation Association by deciding to keep northern Weld County in the ‘nonattainment area’ for ground level ozone. This decision means that polluters in northern Weld County will continue to be held to the higher air quality standards required in the nonattainment area.

The nonattainment area is designated by EPA as an area that fails to meet the 2015 ozone National Ambient Air Quality Standards. In Colorado, it stretches along the Front Range from Castle Rock in the south to Fort Collins and the Wyoming border in the north and west into Rocky Mountain National Park. Weld County unsuccessfully argued in the courts that the northern part of their county – which includes large numbers of oil and gas operations – should be exempt. Oil and gas production emits methane and volatile organic compounds (VOCs), which fuel the climate crisis and are ultimately dangerous to respiratory health.

“At its heart, this case was about how lines are drawn around sources of air pollution in the Front Range,” said Commissioner Claire Levy. “Oil and gas operations contribute to the Front Range’s dangerous air quality and public health crisis. Air pollution, including ozone, travels across political boundaries. We welcome the court’s decision to hold northern Weld County, with its large number of oil and gas operations, to the same air quality regulations as the rest of the Front Range.”

“Low-income communities are more likely to suffer from the impacts and ill-effects of air pollution so ensuring the highest standards is not just about health, but about environmental justice and equity,” said Commissioner Marta Loachamin. “The Boulder County Commissioners will continue to fight for the health of all community members, especially those with respiratory illnesses and anyone whose job requires them to work outdoors.”

“The court’s decision will reduce harmful emissions from the numerous oil and gas sites in northern Weld County,” said Commissioner Ashley Stolzmann. “This will have the added co-benefit of improving air quality conditions and ecosystem health at Rocky Mountain National Park. Additionally, reducing methane emissions from oil and gas operations is critical to tackling the climate crisis. Methane is a greenhouse gas that is 25 times more potent than carbon dioxide at trapping heat in the atmosphere.”

What is ground level ozone?

Ground-level ozone is a key reason the Front Range’s summer air quality is so dangerous to our health.

Invisible and harmful, ozone forms when nitrogen oxides and volatile organic compounds meet in sunlight. The source of Boulder County's ozone problem is mainly oil and gas operations and vehicle fumes, which get trapped against the mountains. Not only does climate change exacerbate ozone season, but ozone itself is also a greenhouse gas, which contributes to the overall warming of the planet.

Breathing ground-level ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ozone also can reduce lung function and may permanently scar lung tissue.

Those most affected by air pollution include children, the elderly, those with respiratory conditions, and everyone who works or plays outside.


  • In 2018, EPA had originally designated northern Weld County as attainment for the 2015 ozone National Ambient Air Quality Standards – exempting them from higher air quality regulations.
  • Boulder County and the organizations listed above challenged that decision in the U.S. Court of Appeals for the D.C. Circuit because northern Weld County contains large numbers of oil and gas operations that are major contributors to ozone.
  • In 2020, the county’s legal challenge was successful, and the court sent the matter back to EPA to reconsider resulting in EPA’s reversal of the original decision.
  • EPA then designated northern Weld County nonattainment for ozone, but Weld County sued in the D.C. Circuit.
  • In 2022, Boulder County, NPCA, Sierra Club, and the Center for Biological Diversity intervened in that case to defend EPA’s nonattainment designation, and in June 2023, the appeals court ruled in the county’s favor.

Collage of all three Boulder County Commissioners