Report: Cheyenne’s air quality worsens in recent years

Cheyenne’s grade fell from an A to an F for the number of high ozone days, despite being ranked first among the cleanest air cities for ozone pollution in the nation last year. It also dropped to third place in the 2023 rankings for the cleanest U.S. cities for year-round particle pollution, while two cities in Hawaii rose to the top.

Nick Torres, director of advocacy of the American Lung Association, said it is not unheard of to have a low grade in one area and a high ranking in another. He said it depends on what is causing air pollution, whether it’s oil and gas drilling, transportation or wildfires.

“That was something that we were seeing in Cheyenne,” he told the Wyoming Tribune Eagle. “There were a couple of instances of stratospheric intrusions that impacted ozone levels, specifically around the Cheyenne region, that had a major impact on ozone.”

Laramie County declined in the rankings for the cleanest counties for year-round particle pollution, dropping from eighth place to 16th. Fremont County rose to the first-place position, and Sublette County replaced the largest county in the state at eighth place.

However, Laramie County maintained its D grade for short-term spikes in particle pollution, which the American Lung Association said can be dangerous and even deadly.

The Wyoming Department of Environmental Quality noted in a statement that their Air Quality Division uses the U.S. Environmental Protection Agency's methodology for health-based standards, and "the American Lung Association’s methodology for calculating 'grades' differs from EPA’s health-based standards methodology."

DEQ officials said the "State of the Air" report is for years 2019-21, and during this time period, Wyoming air was significant impacted by prolonged wildfire smoke from within and outside the state.

"While the AQD understands that the public could be exposed to this pollution, regardless of the source, these wildfire events cannot be controlled by Wyoming’s air pollution regulations," DEQ officials said. "Wyoming can and does control emissions from industrial sources that we regulate. Though the ALA recognizes wildfires as a contributing factor, they still add wildfire pollution to their grading system, even though Cheyenne/Laramie County is meeting all of EPA's health-based standards."

The department said it ensures ambient air quality in Wyoming is maintained in accordance with the National Ambient Air Quality Standards.

Statewide trends

Compared to the 2022 report, many other Wyoming counties experienced significant increases in the number of unhealthy days of high ozone in this year’s report.

Albany County’s grade for ozone pollution also declined from an A to an F, and Campbell County went from a B in the 2022 report to an F this year. Sublette County maintained its F grade, and Weston County was the only county to report a slight improvement in ozone pollution.

Campbell, Fremont, Sublette, Sweetwater and Teton counties each experienced more unhealthy short-term particle pollution days, on average, compared with last year’s report. But Park and Sheridan counties improved in short-term particle pollution, earning them a spot among the nation’s cleanest counties in this category.

The Wyoming Department of Health and Cheyenne-Laramie County Public Health didn’t respond to requests for comment on the data.

Not every county has the chance to be graded by the association. This year, nine of Wyoming’s 23 counties couldn’t provide data on even one measure of air quality.

“One of the things we advocate for nationally is for more funding to be available for more localities to have air monitors,” said Torres. “The locations and the number of air monitors are determined by a few different factors. Both state and federal partners prioritize the places that they’d like to have those air monitors in place.”

National findings

Nationally, the report found that nearly 120 million people, or more than one in three U.S. residents, live in counties that had unhealthy levels of ozone or particle pollution.

“Overall, this is 17.6 million fewer people breathing unhealthy air compared to last year’s report,” according to the key findings of the 2023 State of the Air report. “The improvement was seen in falling levels of ozone in many places around the country, the continuation of a positive trend that reflects the success of the Clean Air Act. However, the number of people living in counties with failing grades for daily spikes in deadly particle pollution was 63.7 million, the most reported in the last 10 years.”

There is also a disproportionate number of people of color who live in areas with unhealthy air quality. Out of the total 120 million people, more than 64 million are people of color.

“In fact, people of color were 64% more likely than white people to live in a county with a failing grade for at least one measure, and 3.7 times as likely to live in a county with failing grades for all three measures,” the report revealed.

Western disparity

A widening disparity between air quality in eastern and western states was also found, especially when it came to particle pollution. The report added data on particle pollution in 2004, and 106 counties in 30 states received failing grades for daily spikes in particle pollution that year. Forty-four of those counties were in eight states west of the Rocky Mountains, but it has continued to rise.

In 2023, 111 counties in 19 states received F grades for daily particle pollution, and all but eight counties were in the West — including Teton County. The same was observed for annual particle pollution, as all of the 17 failing counties were in western states this year.

“Wildfires in the western U.S. are a major contributing factor to the increasing number of days and places with unhealthy levels of particle pollution,” the report noted when it comes to short-term particle pollution trends. “They are also increasing the severity of pollution, resulting in a sharp rise in the number of days designated as either purple or maroon. These are the levels on the Air Quality Index that carry the strongest health warnings.”

Front Range connections

Just 100 miles south of Cheyenne, Denver was added to the top cities most polluted by daily particle pollution. Colorado’s capital city was new to the list and posted its highest-ever weighted average number of days with unhealthy levels of particle pollution.

All but two of the 25 worst cities for daily particle pollution are in the West.

Denver and Fort Collins were also ranked in the top 25 cities most polluted by ozone smog, “which makes breathing difficult for Americans nationwide more than any other singular pollutant.” But national trends show ozone air pollution is heading in a positive direction, which the report credited to the replacement of polluting engines, fuels and processes.

Although getting to Denver takes nearly an hour and a half by car, there is still a connection to other communities on the Front Range.

“We’ve had a number of really devastating wildfires here on the Northern Front Range and Colorado, and I know certainly parts of Wyoming are not immune from wildfire smoke. I think we’re all connected in that,” said Torres. “Part of that is because of the accelerated changes that we’re seeing because of climate change, making wildfires more frequent and more severe because of much drier, hotter climates.”

Air quality impacts

Low air quality isn’t just a number on a data sheet. The American Lung Association and other global health organizations point to the impact it has on human health.

“Years of scientific research have clearly established that particle pollution and ozone are a threat to human health at every stage of life, increasing the risk of premature birth, causing or worsening lung and heart disease, and shortening lives,” the report explained. “Some groups of people are more at risk of illness and death than others, because they are more likely to be exposed, or are more vulnerable to health harm, or often both.”

Particle pollution “refers to a mixture of bits of solids and liquids in the air that we breathe,” and can be traced to factories, power plants and vehicles. There are other sources, such as wildfires, burning wood or residential fireplaces.

The body does have a natural defense system to keep “coarse particles we inhale out of the deepest parts of our lungs,” but the ultra-fine particles go into the air sacs of the lungs and make their way into the bloodstream.

There are risks with both short-term and long-term exposure, and they can impact the daily life of a U.S. resident.

“When Rev. Jenny Wynn wakes up in the morning, she checks two things — the weather and the air quality. As someone with asthma, high air pollution days force her to limit the time she spends outdoors,” according to a testimonial. “Wynn says she often has to consider whether eating a meal outside or running errands on a day with poor air quality might trigger an asthma attack.”

Ozone pollution is a gas composed of molecules with three oxygen atoms, and comes together with other pollutants in a series of chemical reactions. It takes the right conditions, but the report said it can show up “downwind of the sources of the original emissions, sometimes many miles from where it is formed.”

“NOx and VOCs are produced primarily when fossil fuels such as gasoline, diesel, oil, natural gas or coal are burned or when solvents and some other chemicals evaporate,” the report said. “NOx is emitted from power plants, motor vehicles and other sources of high-heat combustion. VOCs are emitted from motor vehicles, oil and gas operations, chemical plants, refineries, factories, gas stations, paint, consumer products and other sources.”

It’s considered a powerful lung irritant and can cause breathing problems such as asthma or COPD. There are more fatal damages noted in medical research from 2017.

The American Lung Association has put forward recommended actions for individuals, local governments and the federal government to improve air quality, but Torres said it may not all be under the control of air quality officials when it comes to exceptional events. He said increasing awareness is one of the most important first steps.

“We hope that the public can be vigilant when it comes to air quality,” he said. “I think there might be a misconception that ozone is only for big cities, or only for certain areas of the country. But we want to make sure that everyone’s paying attention to the air quality in their communities so that they can protect themselves and their loved ones.”

This story was updated Thursday morning to include a response from the Wyoming Department of Environmental Quality.