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Front Range air quality is terrible, but Colorado’s efforts are showing some improvement in ozone pollution

A slate of new laws is expected to speed up air-quality improvements, but Denver still hasn't met standards that the EPA set more than a decade ago

A layer of haze covers the view of Pikes Peak rising over the south Denver metro area on Sunday, Nov. 4, 2018. (Jesse Paul, The Colorado Sun)
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If the weather this summer is anything like it was in 2011, Front Range residents might think they can breathe a little bit easier than last year’s sweltering season.

Cooler temperatures and regular afternoon monsoons eight years ago kept the area’s ground-level ozone — the heated air we breathe with trace bits of fumes from cars, power plants and even lipstick — to a natural minimum.

But don’t breathe a sigh of relief just yet. There was plenty of pollution in the Denver area in 2011 and air quality was deemed so unhealthy that the region failed to meet a federal air quality standard set in 2008. The region is still out of compliance today and forget about meeting a stricter one set in 2015.

That’s the Regional Air Quality Council’s task: Figuring out how to get the nine-county metro Denver region into compliance with the Environmental Protection Agency’s old and new standards, set at 75 parts per billion of ozone in 2008 and at 70 as of 2015. (Last year, several sites in the Denver region were in the high 70s to low 80s parts per billion.)

“We have an issue with ozone. It’s our summertime air pollutant and we’re not attaining the federal standard,” admitted Mike Silverstein, executive director for the air-quality planning agency for the Denver metro area.

Mike Silverstein, executive director of the Regional Air Quality Council, stands next to a poster at his office in Denver. He works with members in the nine-county metro region to figure out next steps to get the region’s air quality into EPA compliance. Silverstein previously served on the Colorado Air Quality Control Commission and worked as an air quality planner for the Colorado Air Pollution Control Division. (Tamara Chuang, The Colorado Sun)

But Silverstein said all of our efforts to reduce emissions haven’t been for naught. The region has steadily seen a decline.

“But no matter what you might hear or what others might say, ozone pollution (in the Denver area) is actually improving,” he said. “It’s the standards that are getting tougher. We have to recognize that it’s the EPA’s job to assess the appropriateness of the standard and when necessary, change the standard to protect public health. The new standard is 70. That’s the new goal — get to 70 here in the next five years.”



If you read only read the words “ozone … is … improving,” it is — at least on moderate summer days with no hint of wildfires.

Some things are out of state control, from plant emissions to geography to ozone coming from neighboring states. But emissions that can be lowered through human control have declined.

Silverstein, who worked as an environmental scientist for the EPA in the mid 1980s, credits this to automakers making cars that pollute less, oil companies sealing up methane leaks and capturing escaping emissions, and a slew of new laws and government regulations that are expected to minimize emissions further in Colorado.

It may never be enough to clean the air sufficiently for those suffering from asthma or other respiratory issues. But it’s a clear path that Gov. Jared Polis is speeding along. He chose to withdraw a federal waiver that would have given the region more time to comply and stop counting pollution wafting in from Mexico, Canada and other countries in the total.  

The region now faces stricter federal regulations.

That withdrawal was too much for Defend Colorado, a nonprofit that won’t disclose its members. It filed a lawsuit in April accusing Polis of violating the state constitution by “improperly influencing” the Air Quality Control Commission, a rule-making body that was considering the waiver. Withdrawing means the EPA will label the region as “serious nonattainment” and that will add “mandatory increased federal regulatory oversight,” according to the lawsuit.

“It’s pretty far reaching and pretty impactful” to businesses, said Paul Seby, an attorney for the nonprofit. “It’s hard to say what the ultimate impact of them is, but that’s the problem with giving such a blank charge to the agency. But it’s certain to result in some pretty dramatic regulations in the name of the ozone and climate.”



Such waivers are typically used in rural areas that are near an international border, such as El Paso, Texas. Studies showed that emissions from nearby Juarez, Mexico, were much higher and without them, El Paso would have reached EPA attainment.

Colorado isn’t near an international border and so, to claim the waiver, the state would have to prove emissions came from outside the United States instead of local vehicle traffic or industry. Also, the EPA has not provided guidance for the state to study the impact of foreign emissions, said Amanda Brimmer, the Regional Air Quality Council’s technical program manager.

“No inland state has attempted to use this provision and, for Colorado, being an inland state, and with the Denver Metro/North Front Range being a metropolitan area with significant sources of locally produced emissions, the bar would be much higher for our region to make such a demonstration,” Brimmer said.

Getting to compliance through shortcuts still leaves unhealthy air, and that is unacceptable, Polis said.

“When I found out that Colorado was using delay tactics to prevent making our air cleaner, I was outraged,” he said in a statement to The Colorado Sun.

“Last year alone, there were 44 ozone action days when Coloradans were warned that exercising outdoors could be damaging to their health due to a high ozone level,” he added. “Kids, athletes, and seniors feel the impact of smog first, but it hurts all of our health. We can’t sit back and rely on waivers or blame other countries for our own air quality problems. We have to do everything in our power right here at home to make our air cleaner and our people healthier as soon as we possibly can.”

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Getting to EPA compliance via legislation

On Thursday, Polis signed seven energy bills approved by the Democratic-led General Assembly earlier this year.

The new regulations help lay the groundwork for Colorado to move closer to 100% carbon-free energy by 2040 — a major campaign promise the Democrat made in 2018.

“What does that mean for every Coloradan? It means cleaner air. We have an air quality crisis across the Denver metro area with significant health impacts,” Polis said before he signed the bills at SunShare, a solar power company.

The legislation to address climate change follows the lead of other states, but for Colorado, it collectively represents one of the most comprehensive efforts in the nation to address energy consumption and move toward carbon-free power sources.

Gov. Jared Polis speaks to a crowd on Thursday, May 30, 2019, before signing a slate of bills meant to improve Colorado’s air quality. (John Frank, The Colorado Sun)

“We ended up with, I think, the most historic piece of energy legislation in state history,” said state Rep. Chris Hansen, a Denver Democrat, referring to Senate Bill 236, a 64-page bill to overhaul the Public Utility Commission and mandate the consideration of the “social cost” of greenhouse gas emissions.

Polis disclosed that he will take executive action to push the effort even further, but in an interview with The Colorado Sun he refused to offer more details.

Entering the session, Democratic lawmakers made climate change a priority, and outlined a strategy to address various facets of the issue in a way that combines for great effect.

Other measures signed into law include new state-level energy standards for more than a dozen appliances, such as commercial kitchen equipment and computer monitors, that have no federal benchmarks, the creation of an office to manage workers’ transition from the fossil fuel industry and expanding the amount solar power companies can generate and feed into the electric grid.

MORE: Climate change is a priority at the Capitol. These charts show how far Colorado needs to go.

A major bill puts goals to reduce carbon emissions into state law, requiring cuts of 26% by 2025, 50% by 2030, and 90% by 2050 from 2005 levels. The legislation leaves it to the state’s air quality commission to write the regulations to achieve the goals.

Republican lawmakers warned that the commission would impose “draconian regulations,” in particular when it came to vehicle emissions.

Sen. John Cooke, R-Greeley, introduced legislation this session to block the commission from adopting standards more stringent than federal regulations, such as those in California, but Democrats defeated it. “Allowing an unelected board of appointed bureaucrats to implement standards from another state — resulting in an increase to vehicle costs — is contrary to the purpose of government,” he said at the time.

The big cleanup

In the 1980s and 1990s, air quality regulators didn’t sniff around oil and gas fields — the industry was exempt from federal air quality regulations, Silverstein said.

“It wasn’t viewed as a significant source,” Silverstein said. “But in the early 2000s, the boom really began in Colorado and development started to really surge. And we discovered that this was a much bigger source. There were a lot of emissions coming from oil and gas that were contributing to the ozone.”

Under Gov. John Hickenlooper, Colorado adopted laws in 2014 requiring energy companies to inspect their well pads for methane leaks and make repairs.

Colorado was the first state to do this, but it wasn’t because of federal pressure. “No, it was only because we knew we couldn’t comply with the ozone standards,” Silverstein said. The EPA went on to adopt similar rules nationwide, although those now face a rollback by the Trump administration because of petroleum industry complaints that they’re burdensome.

Lynn Granger, executive director of the Colorado Petroleum Council, said the industry in Colorado took a leadership role in reducing its emissions by working with regulators to reduce emissions. Limiting methane emissions has resulted in an estimated reduction of “more than 60,000 tons of methane emissions per year, as well as reduce 92,000 tons of VOC (volatile organic compounds) emissions per year,” Granger said in a statement.

“Colorado’s natural gas and oil industry takes seriously its commitment to environmental stewardship, because this is our home, too,” she said.

Where is pollution the worst along the Front Range?

The northern Front Range (Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, Larimer and Weld counties) has not yet met a 2008 federal standard for healthy air quality. As pollution worsened, the EPA is expected to classify the area as “serious nonattainment.” The worst areas include Rocky Flats, Chatfield State Park, west Fort Collins and the National Renewable Energy Laboratory near Golden.

The state continues to explore air-quality improvements in the oil and gas sector, which is the top contributor to the region’s ozone pollution. The transportation industry is second. That’s why Polis is pushing for a zero-emission-vehicle mandate, which would require automakers to make electric vehicles a certain percent of their inventory available in Colorado or face fines.

The Colorado Automobile Dealers Association claims the mandate will hurt the environment because cost-conscious consumers will keep their old gas guzzlers longer (gasoline cars haven’t been outlawed).

Newer gasoline cars run much cleaner today with passenger vehicles that “are 98 to 99% cleaner for most tailpipe pollutants compared to the 1960s,” according to the EPA. The dealers organization focuses on its Clear the Air Foundation, which has taken 4,000 older vehicles off the roads since its 2011 launch.

“The main point we seek to cover is taking higher emitting cars off the road and replacing them with newer cleaner cars (which) is helpful to both particle emissions (ozone, brown cloud, asthma) as well as carbon emissions,” CADA president Tim Jackson said in an email.

If the state had sat around and done nothing for years, Silverstein said, the area’s ozone pollution would probably be where it was in the 1980s, when it was in the 90s or 100s parts per billion, instead of today’s high 70s and 80s. And since then, the population has increased, there are more cars on the road and industries have grown, he said.

“This wouldn’t have been allowed to continue,” he said of the high ozone pollution. “If the EPA says you’re not trying, we’re going to sanction your federal highway dollars. And no more federal permits for new industrial sources. No growth for you. If company X wants to move here, sorry, you can’t because of federal sanctions of permits.”

EARLIER: The Front Range fails to meet federal standards for healthy air quality. Again.

As EPA restrictions have tightened, the Regional Air Quality Council has had to search for new ways to limit emissions from volatile organic compounds (VOCs) or nitrous oxide (NOx), which chemically react to heat and cause ozone pollution. Colorado could switch to a “summer blend” of gasoline like in California that is more costly at the pump but is designed to be less evaporative and thus reduce pollution.  

Consumer items like household paint, shoe polish and even lipstick (“If it has a scent, it has a little VOC,” Silverstein said) are being looked at by the council to see if existing water-based alternatives could replace the smelly products sold in Colorado.

Sometimes, local industry is proactive. For instance, members of the cannabis community met with the council to consider the impact of marijuna odors from large industrial warehouses.

“That’s a VOC, and that’s a natural emission that regularly causes ozone that we didn’t have five years ago, or when the pot laws started. We have a big new source now,” Silverstein said. “We just had a presentation from them saying what can we do as an industry to reduce our own emissions (and suggesting) carbon filtration, different plant strains and all kinds of activities.”  

Left: Downtown Denver on July 10, 2018 at 1 p.m., a day when the Front Range was under an Ozone Action Day alert and the mountains were difficult to see. Those with health conditions were advised to stay indoors. Right: Downtown Denver on Oct. 17, 2018 at 1 p.m., a day with no air pollution advisories and good air quality. (Provided by Colorado Department of Public Health and Environment)

There’s also been work done to better predict bad ozone days and encourage voluntary action. Companies could postpone replacing a valve or making a delivery until the air clears. This summer, Front Range temperatures could be cooler due to El Niño conditions in the eastern Pacific Ocean, said Scott J. Landes, supervisor and air quality meteorologist at the state’s Air Pollution Control Division.

“Although predicting ozone on a seasonal basis is incredibly difficult, there are some hopeful indications that ozone this summer may be generally lower than last year,” Landes said in an email. Above-normal precipitation is forecast this summer for the Front Range, he said, adding, “Clouds and rain generally lower ozone concentrations, so to that end we are cautiously encouraged about the long range forecast.”

Jacob Smith, executive director of Colorado Communities for Climate Action, applauds Polis’ efforts. Without the nudge of regulations, he said industry doesn’t move fast. Technology to prevent oil wells from leaking methane, for example, were available but weren’t used until policy caught up. One of the state’s new laws requires electric utilities to consider the hidden cost of emissions by building a tool to calculate the impact on consumer health.

“We know that in order to bring down air pollution levels, it requires a combination of better regulations and better incentives,” Smith said. “Colorado really does have air quality problems still, and they are serious. By directly attacking those sources of pollution, that’s a huge part of how we are going to solve the problem.”

This story was updated June 3, 2019 with comments from Lynn Granger, Colorado Petroleum Council’s Executive Director.


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