Colorado violates EPA ozone standards again

Business groups cheer weakening of draft commuting limits

Michael Booth
The Colorado Sun
Posted 7/23/21

On the same day environmental groups called out Colorado officials for missing a key EPA deadline to clean up ozone pollution violations widely attributed to driving, business groups declared victory …

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Colorado violates EPA ozone standards again

Business groups cheer weakening of draft commuting limits


On the same day environmental groups called out Colorado officials for missing a key EPA deadline to clean up ozone pollution violations widely attributed to driving, business groups declared victory in weakening the state's new set of rules to reduce air pollution caused by employee car commutes.

The double whammy was not lost on conservationists, who took one look at the watered-down state rule proposal and how the Colorado Chamber of Commerce was celebrating it and issued louder warnings.

“As the region misses another ozone pollution reduction deadline and we are stuck in a series of dirty air days, now is not the time to gut the (commuting) rule, and I'm disappointed in the position our state health department put out,” said Danny Katz, executive director of the nonprofit consumer activist group CoPIRG. “The smoke alarm is blaring. We need to all work together to put out the fire and have the clean air every Coloradan deserves.”

Overall air quality on the Front Range, and a subset of measurements of ground-level ozone dangerous to human health, have improved in recent years, but the EPA has repeatedly lowered the maximum limit of ozone scientists consider safe. That means Denver and other Front Range counties have been violating the ratcheted-down limits, and July 20 was another EPA deadline for the area to come into “attainment” or face new consequences.

State health and conservation officials have said they now expect the EPA to further downgrade the Front Range zone into the next-lower “severe” category from the current level of “serious” violations. Lowering the rating again will mean local governments must go back to the drawing board for regulations cutting pollution through limits on driving or demands for cleaner fuels. Meeting the standards will also likely mean tougher rules for oil and gas producers venting chemicals, and cutting emissions by an array of industries.

The state Air Quality Control Commission is scheduled to hear new sets of proposed rules on employee commuting in August, and the staff of the Colorado Department of Public Health and Environment had previously put out drafts seeking mandatory commuting cuts for large employers starting in 2022. Conservationists wanted tougher enforcement provisions of those rules, but had said they were a good start toward finally attacking the transportation-related sources of air pollution and greenhouse gases.

Goals become `aspirational'

Then CDPHE issued a statement the week of July 19 saying it had run into opposition from employers and their associations, and would shift to emphasizing employer-run surveys of commuting habits and “aspirational” goals for reducing miles driven.

“This new proposal is based on the recognition that lasting and meaningful success will require strong buy-in from employers and employees who are subject to the program, and a pilot phase will facilitate our understanding of real world implementation successes and challenges,” the CDPHE's statement said.

The Colorado Chamber of Commerce praised the new, lenient direction.

“How Coloradans commute to work shouldn't be the concern of state government, and a mandatory approach to reducing employee commutes would be overreaching, impractical and inequitable,” said Katie Wolf, director of the chamber's state governmental affairs, in a statement. “We appreciate that the commission has taken our feedback seriously and will be revising its proposal from a mandatory to voluntary program.”

CoPIRG's Katz said Denver and the northern Front Range counties in the non-attainment area have failed to contain ozone for years, and that “fossil-fuel powered vehicles” are a key contributor. July 20 was the latest EPA deadline for Colorado to make progress, Katz noted.

The proposed commuting rule, dubbed ETRP by the state, “offered a chance to align large employers and expand options for employees to do their jobs without commuting and adding more pollution to our air,” Katz said.

The arguments come as the Front Range bakes under another heat wave that has consistently raised ozone counts toward dangerous levels. On July 20, Colorado state monitors reported a peak of ozone at 74 parts per billion in the Denver metro zone at 2 p.m., a level they call “unhealthy for sensitive groups.”

Ground-level ozone is caused by a mix of volatile organic compounds released by oil and gas and other industries, vehicle emissions and power plant emissions, and made worse by the hot sunshine metro Denver gets most of the summer. James Crooks, a National Jewish Health epidemiologist and professor, said at an event with CoPIRG on July 20 that rising temperatures from global warming are making the ozone mix far worse.

“We need to be making changes in the near future” to ozone-producing activity, Crooks said.

EPA tightens standards

In 2008, the EPA benchmark for ozone was 75 parts per billion. That was lowered in 2015 to 70 parts per billion, and some scientists maintain the health standard should fall even lower than that.

Bill Hayes, air quality program coordinator for Boulder County Public Health, noted at the CoPIRG event that Colorado had already put out 27 ozone action day alerts in 2021, worse than last year's pace. In recent years, the average high readings for ozone in the non-attainment area have been in the upper 70s and lower 80s, well short of the EPA goals, Hayes said.

In the state air quality staff's first proposal, Colorado businesses in high-ozone areas that have more than 100 employees on-site would have to limit the number of workers commuting alone in cars to 75% of their workforce starting in 2022 and 60% by 2024. Those employers would also have appointed an official transportation coordinator and eliminated parking subsidies, or started charging for currently free parking.

While those rules were specific, immediate and apparently mandatory, they did not come with enforcement provisions. There were reporting and recordkeeping requirements, but they also said that employers missing the goals could file “alternative compliance plans.”

The CDPHE statement on July 20 said the revised draft rules will “first focus on data gathering components to establish a strong baseline for future policy.”

The goal, but not a mandate, the CDPHE staff statement said, would be “aspirational single occupancy vehicle drive rates of 60% or less by 2025 to be demonstrated through employers' survey reporting.”

This story is from The Colorado Sun, a journalist-owned news outlet based in Denver and covering the state. Used by permission. For more, and to support The Colorado Sun, visit


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