Colorado is giving up on near-term ozone improvements in favor of longer outlook

Colorado is giving up on meeting mandates for controlling toxic ozone in the next few years, while doubling down on plans that recently passed rules will start to make an impact by 2032. 

Colorado Department of Public Health and Environment officials say they are asking the federal EPA to preemptively downgrade the Front Range ozone nonattainment zone to “severe” from the current “serious” violation standard, when judged by the 2015 ozone cap of 70 parts per billion. 

Recent updated computer modeling of Front Range air shows continuing violations closer to 80 parts per billion, according to Regional Air Quality Council Executive Director Mike Silverstein. The RAQC is an advisory board and not a policy-making agency, but was briefed by the state about the downgrade request.

That means Colorado isn’t projected to meet even the more lax 2008 standard of 75 parts per billion before 2027, Silverstein added. 

Yes, it’s confusing: The nine northern counties included in the nonattainment area are on parallel but different schedules to cut lung-damaging ozone, one schedule whose clock started with the 2008 regulations and another schedule launched with the tighter 2015 standards. 

The bottom line is Colorado is failing on both tracks. 

For the 2008 track, Colorado has submitted to the EPA for approval an improvement plan aimed at getting closer to the 75 ppb standard by 2027. On that 2008 track, Colorado has already been downgraded to “severe” violations. 

The first year of monitoring actual ozone for that plan was 2024, “and we didn’t start off well in our first year,” Silverstein said. 

“So we need to have much better summertime air quality these next two years,” he added. 

Is that likely? 

No. New modeling run by the state “doesn’t predict we’re going to make it to 75” in 2025 or 2026, Silverstein said. “Our emission trends are flat,” he said. 

The state asking for a “severe” reset on the 2015 track buys time and moves the deadline for achieving 70 ppb to August 2032. 

The state’s action, detailed in a letter to the advisory Regional Air Quality Council in late March, also helps Colorado avoid some of the additional EPA sanctions that would have come from leaving nonattainment in the “serious” category and then officially exceeding those caps. By moving to “severe,” Colorado avoids having to submit a new improvement plan on the 2015 standards during 2025, and skirts these new sanctions: 

• A requirement that proposed pollutants from new or modified large-source facilities be offset 2-to-1 by emissions cuts elsewhere in the nine-county area before projects could move forward.
• Federal highway funding sanctions that could hold back money for important Colorado transportation projects. 

Colorado’s request does involve, though, adding some new territory into the nonattainment area. Far northern Weld County will now be included, along with the remainder of Weld, part of Larimer, and all of Boulder, Jefferson, Denver, Broomfield, Adams, Douglas and Arapahoe counties. The change means new oil and gas developments in northern Weld will be subject to more state scrutiny in permitting. 

Does Colorado have any chance of making big improvements in those outlying years, even with the bonus time from seeking the second “severe” downgrade? 

Colorado and RAQC officials cite these recent laws or policies as examples of potentially effective ozone-cutting practices that could start changing the results on monitors by 2030 to 2032: 

• Ongoing state subsidies for purchasing clean electric or plug-in hybrid electric vehicles, attacking ozone in the stubborn area of transportation. 
• A series of new rules meant to cut ozone and greenhouse gas-causing emissions from the oil and gas industry, including “midstream” controls at oil and gas gathering and pipeline operations, and sharp cuts to allowed nitrogen oxide produced in upstream oil and gas.
• Rebates to buy clean lawn and garden equipment and restrictions on when large institutional users of gas-powered equipment can use the highly polluting engines in high ozone summer months. 
• Advanced clean trucks rules requiring makers of heavy-duty commercial vehicles to start selling an increasing percentage of electric or otherwise clean-fuel models beginning in the 2027 model year. 

Colorado’s request for a downgrade, said RAQC spokesman David Sabados, “in no way reduces our sense of urgency.”