Colorado Tightens Air Rules to Cut Ozone Pollution 50%

The Colorado Air Quality Control Commission has approved a broad set of regulations and State Implementation Plan updates designed to reduce ozone-forming emissions from upstream oil and gas operations, expand leak detection requirements, and strengthen controls across several high-polluting sectors.

• By Stasia DeMarco
• November 24, 2025

Colorado regulators have adopted a sweeping set of air quality measures aimed at reducing ozone-forming emissions from upstream oil and gas operations by 50% by 2030, state officials said Friday.

The Colorado Air Quality Control Commission approved regulatory updates and revisions to the state’s air pollution control plan, marking one of the most significant clean-air initiatives the state has advanced in recent years. The reductions are measured against 2017 levels.

“Clean air is the foundation for a thriving and sustainable community,” said Michael Ogletree, senior director of state air quality programs. “With these strategic actions, the state reaffirms its commitment to protecting the health of our residents and the environment for future generations.”

Ground-level ozone is a harmful pollutant linked to lung problems, particularly among children, older adults and people with respiratory conditions. It forms when volatile organic compounds and nitrogen oxides react in sunlight and heat. Major sources in Colorado include gasoline-powered equipment, vehicles, and oil and gas operations.

The commission’s action follows a 2023 directive instructing state agencies to craft rules that would cut nitrogen oxide emissions from upstream oil and gas facilities in ozone nonattainment areas — regions that fail to meet federal ambient air quality standards.

Under the approved regulations, Colorado will expand leak detection and repair requirements, strengthen emissions controls, and widen oversight of equipment that releases ozone-forming pollutants. The measures include updates to:

• Regulation 7, which extends the nitrogen oxide intensity program and expands leak detection and repair rules for oil and gas operations, including storage and transfer systems.
• Regulation 11, identifying more high-polluting vehicles for emissions oversight.
• Regulation 25, placing stricter limits on volatile organic compounds in aerospace coating materials.
• Regulation 26, tightening emissions controls for combustion equipment and industrial waste processes in northern Weld County.

Many of the updates were incorporated into Colorado’s State Implementation Plan, the roadmap outlining how the state will reduce ozone pollution in nonattainment areas. The revised plan also allows for further technical study to support future policy decisions.

The commission also approved changes to administrative procedures and regulatory language to ensure long-term sustainability of ozone reduction programs, including the federal vehicle emissions testing program. The revisions also update modeling rules and emissions credit procedures to simplify compliance for regulated industries.

In a separate move, the commission backed a proposal to voluntarily reclassify a smaller section of northern Weld County as nonattainment for the 2015 ozone standard. If approved by the U.S. Environmental Protection Agency, the reclassification would allow the state to direct more resources toward cutting emissions without taking on additional federal administrative requirements.