Relentless dry heat, combined with a recent spate of wildfires, has created a summer bane for the Mountain West: near-daily spikes in ozone and other air pollutants collectively known as smog.
Colorado’s Denver metropolitan area and northern Front Range, which stretches from the Wyoming border to Boulder, have continued to violate federal ozone standards for years, despite significant improvements in emissions control in both the transportation and energy sectors.
Experts believe the continued seasonal increase in the colourless gas, which can affect respiratory and cardiovascular health, is due to a combination of factors including climate change, population growth and the region’s unique topography.
“There have been a lot of efforts to reduce pollution through cleaner cars and better regulation of oil and gas,” Anthony Gerber, director of lung research at National Jewish Health, told The Hill.
“At the end of the day, we’re just treading water because of climate issues and the expansion of the Front Range,” Garber said.
Unlike the atmospheric ozone layer, which protects people from solar radiation, ground-level ozone poses a potential threat to people who inhale it, especially those who are already sensitive.
This type of ozone is produced by mixing pollutants such as nitrogen oxides and volatile organic compounds (collectively known asOzone PrecursorsAccording to the Colorado Department of Public Health and Environment, the plant responds to sunlight and heat.
These compounds come from sources such as gasoline-powered vehicles, industrial exhaust fumes, oil and gas operations, and particulate matter in wildfire smoke. The precursors “combine with the atmosphere and ultraviolet light and heat to create ozone,” Gerber explained.
Gerber said the highest ozone concentrations in the region are typically not in urban centers, but rather “closer to the Front Range foothills.”
“The mountains can trap these precursors,” he said, “but during periods of extreme weather — hot, dry, with little wind — ozone levels can increase and affect entire urban areas.”
This summer has been dry and smoky in recent weeks, due to wildfires thousands of miles away and a series of local fires.
Mike Silverstein, president of the Regional Air Quality Council, explained that although the region has prevailing winds that move from west to east, mountain ranges block the air flow at ground level.
Silverstein described the “bathtub effect” during the day, saying warm air rises up the hills and pumps a mixture of “oil and gas emissions, urban emissions, hairspray and bathroom products, detergents, paints and solvents, car exhaust, all kinds of consumer products” into the atmosphere.
“Sunlight then causes various pollutants to react and become ozone,” said Silverstein, whose agency advises the state on air quality in nonattainment areas of the Denver metropolitan area/North Front Range.
“It kind of puts a lid on our area, almost like a dome,” he added.
Despite the constant air quality warnings this summer and in recent years, “ozone concentrations and the number of ozone exceedance days have been trending downwards in recent years compared to 20 years ago,” Silverstein said.
He attributed the decline to significant cuts in emissions and increasingly stringent Environmental Protection Agency (EPA) standards for achieving the ozone layer.
Still, Silverstein stressed that ozone standards are exceeded in the region at least 30 days each year, and that conditions change each summer due to meteorological factors.
As for the current surge, Silverstein noted that smoke from local wildfires, as well as wildfires in Canada and California, is a “huge confounding factor.”
Before the fires blanketed the area in smoke over the past few weeks, Silverstein said, ozone levels “had a number of days that exceeded the threshold,” but individual readings were not necessarily as high as in recent years.
“Then, as we started to see the impact of the wildfires, the numbers skyrocketed,” he added.
Many of Gerber’s patients already have compromised lung function, and continued pollution means worsening symptoms like chest tightness. Because these pollutants are inflammatory, Gerber also expressed concern about the possibility of associated strokes and heart attacks.
“I would definitely urge people to take medications that protect their heart when air pollution is spiking,” Gerber said.
Residents of the Rocky Mountain foothills may experience regular spikes in air pollution problems during the summer, but they’re not the only ones in the Western U.S. enduring such seasonal conditions.
Silverstein cited Los Angeles as a prime example of a place where such pollution is particularly prevalent, noting that the “trapping effect” of mountainous terrain helps pollutants build up.
on the other hand,Recent ResearchOil and gas development has recently been linked to summer spikes in ozone levels in Carlsbad Caverns National Park in New Mexico, where pollutant levels often exceed EPA standards due to runoff from the Permian Basin, the authors found.
Garber also singled out Salt Lake City as a vulnerable location, characterizing ground-level ozone as a “region-wide issue,” which he said includes other pollutants such as particulate matter released by wildfires.
“The two substances tend to travel together,” he said, noting that the mixture of ozone and fine particles is traditionally known as “smog.”
Looking back to the past when oil and gas were the primary sources of air pollution on the Front Range, Garber recognized regulatory advances that have helped mitigate those emissions.
“But now we’re facing the dual problem of hot days and wildfires,” Garber said. “The evidence suggests that air quality will continue to hit these dangerous levels more frequently over the next 10 to 20 years.”
Gerber stressed that rather than relying on regulation to solve the problem, strategies need to be developed to increase resilience and change the behavior of residents in ozone-affected areas, for example by exercising earlier in the day.
Silverstein agreed, adding that “it really comes down to lifestyle choices” — making the decision to minimize your use of petroleum-based products, switch from a gasoline-powered lawnmower to an electric one and spend less time driving.
The Regional Air Quality Council has also proposed two bills that would affect oil and gas operators: one that would reduce emissions when wells are shut down for maintenance, and another that would require recapture of certain pollutants.
Another potential solution that researchers recently explored is the possibility that free public transportation might help combat the depletion of the ozone layer.
To that end, they praised an August 2022 initiative in which local public transportation agencies will make all fares free, in the hope that voluntary shifts away from cars will help reduce the ground-level ozone layer.
But Grant Webster, a doctoral student at the University of Colorado Boulder, has studied the impact of such changes. Recently decided They weren’t enough: Webster observed that public transit ridership increased by 15 to 20 percent during the period, while car ridership stayed about the same.
A 1 percent decrease in ozone pollution in Colorado would require a 74 percent to 192 percent increase in public transportation use. Transportation Research.
As the region continues to battle the ozone layer and smog, Gerber stressed the need for both short-term adaptation measures and long-term action to reverse global warming.
“We can’t wave a magic wand and put all of the carbon pollution back in the bottle and have it gone by next year,” he said. “So we need to think smartly about adaptation strategies that minimize the risks to the people who enjoy the great things about life on the Front Range.”
