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Hazy and polluted air over the Denver skyline as seen from Speer Boulevard
As traffic rolls along Speer Boulevard in the foreground, the skyline is shrouded as pollution fills the air Wednesday, March 6, 2019, in Denver. (AP Photo/David Zalubowski)

The worst ozone year in recent history on the Northern Front Range boosted pollutant violations in a rolling three-year average closely watched by the EPA, state officials said Thursday, though they did not offer bold new programs to combat the hazardous substance.

Twelve monitoring sites on the Front Range now have a three-year average over the EPA’s most recent 70-parts-per-billion cap for ozone, and five sites violate even the EPA’s previous looser standard of 75 parts per billion, according to annual reports made Thursday to the Air Quality Control Commission by state and regional pollution officials. 

Widespread Western wildfires and the smoke they shed into Colorado contributed to the ozone worsening in the northern Front Range area already in non-attainment of EPA limits, the officials said. But they also acknowledged that the hot dry summer of 2021, which will be repeated in the future as climate change affects the West, made for terrible ozone conditions — with or without the smoke. 

“Other areas don’t violate the standards like we do,” said Mike Silverstein, director of the Regional Air Quality Council, which tracks pollution and recommends policy changes to help the Front Range meet EPA limits. “So that shows that local vehicle emissions are really what kicks us over the threshold of the standards, not what’s given to us from outside.”

The state Air Quality Control Division staff, which reports to the commission, confirmed that the Northern Front Range is likely to be declared in “severe” violation of EPA ozone limits in early 2022, after lingering in the “serious” violation category. Changing the classification triggers more demands on the RAQC and state officials to clamp down on vehicle emissions and volatile chemicals from oil and gas operations that contribute to ozone. 

ozone air pollution Colorado non-attainment area 2021
The EPA looks at three-year averages when deciding if a metro area is “out of attainment” for its air pollution standards, and Colorado’s ozone problem is getting worse, state monitors show, in a report presented Oct. 21, 2021. The current EPA target for ozone is 70 parts per billion. (Colorado Air Pollution Control Division presentation)

Colorado continues to show progress in other key areas of EPA concern, including nitrogen oxide and volatile organic compounds that are precursors of ozone, the presentations Thursday showed. But ozone is in violation and getting worse, with many Front Range monitors registering levels higher than 80 parts per billion over the summer. 

Some AQCC commissioners pressed staff and RAQC officials making the annual reports on what new measures will be taken soon to bring ozone down. 

“We must own the reality that what we’re doing is simply not enough,” Commissioner Elise Jones said after the meeting. “We are failing on air quality. It’s time for us to pursue bolder solutions than we’ve considered before — like making transit free, and not allowing oil and gas fracking during the ozone season.”

Air quality officials are scheduled to make more rules cutting emissions from oil and gas production in December, and that has proven one of the most effective strategies so far, Silverstein said. RTD has also begun talking about seeking federal funding for free transit on ozone alert days, which would cost millions in foregone ticket revenue, he added. 

Silverstein said RAQC and others will be looking at reducing vehicle miles traveled, a key measure in trying to cut ozone pollution, by working with large warehouse centers, shopping malls or other concentrated locations for vehicle trips. Front Range air pollution monitors can separate out pollution sources and identify which category is most promising for reducing ozone — travel by cars and light trucks  is the top pollution contributor for almost every monitor, the Thursday presentations showed. 

Changing automobile use for employers or employees, though, has proven one of the most fraught avenues in metro Denver’s pollution control efforts. Air Pollution Control Division staff over the summer proposed requiring large employers to cut the number of commuting or work miles driven by staff, but quickly withdrew the Employee Trip Reduction Program on opposition from business and industry groups. 

Silverstein noted that rebates to people who replace gas-powered lawn mowing equipment with clean electric models has also helped make a dent in afternoon ozone. Commissioner Jana Milford noted that California has just moved to end the sale of oil and gas-powered lawn equipment altogether, and wondered if Colorado should follow that lead. 

Reaction from environment advocates after the meeting appeared to be, “all of the above, and more.” 

V. Sean Mitchell, Colorado spokesperson for the Alliance of Nurses for Healthy Environments, said the state’s ongoing pollution problems became more critical with COVID-19, and studies showing the virus does deeper damage in areas made vulnerable by high pollution. 

“The air quality this summer was atrocious,” Mitchell said, in an emailed statement. “Now is the time for Colorado to not shift the blame to other states, but again take the lead, with bold actions to provide clean, healthy air.” 

Michael Booth is The Sun’s environment writer, and co-author of The Sun’s weekly climate and health newsletter The Temperature. He and John Ingold host the weekly Sun-Up podcast on The Temperature topics every Thursday. He is co-author with...