New Report: Cheyenne, Casper Named Among Cleanest Cities in New Lung Association Report

American Lung Association “State of the Air” Report reveals that some Wyoming residents faced more days of poor air quality on average despite cleanest cities rankings.

The 2022 “State of the Air” report, released today by the American Lung Association, finds that Wyoming’s rankings were mixed for some of the most harmful and widespread types of air pollution: particle pollution and ozone. 

Laramie and Casper each ranked among the country’s cleanest cities. Cheyenne appeared on the list of cleanest cities for ozone pollution, with zero unhealthy days, and ranked #1 among cleanest cities for year-round particle pollution. Casper ranked #6 for year-round particle pollution. 

The “State of the Air” report is the Lung Association’s annual air quality “report card” that tracks and grades Americans’ exposure to unhealthy levels of ground-level ozone air pollution (also known as smog), annual particle pollution (also known as soot), and short-term spikes in particle pollution, over a three-year period. This year’s report covers 2018-2020. See the full report at

“Despite some recent improvements, the levels of ozone and particle pollution seen in several areas of Wyoming can still harm residents’ health. But particularly at risk are children, older adults, pregnant people, and those living with chronic disease. Both ozone and particle pollution can cause premature death and other serious health effects such as asthma attacks, cardiovascular damage, and developmental and reproductive harm. Particle pollution can also cause lung cancer,” said Nick Torres, advocacy director for the Lung Association. 

Ground-level Ozone Pollution in Wyoming
Compared with last year’s “State of the Air” report, several counties reported more unhealthy days of ozone pollution, including Albany County and Natrona County. Sublette County showed a slight improvement but still reported the highest number of unhealthy ozone days by far, with a weighted average of 5.8, earning the only F in the state for that category.

Particle Pollution in Wyoming
The report also tracked short-term spikes in particle pollution, which can be extremely dangerous and even lethal. Compared with last year’s report, several counties reported more unhealthy days of short-term particle pollution, including Albany County, Laramie County, and Natrona County. Grades in this category dropped a full letter in each of those counties. Unhealthy short-term particle pollution days increased significantly in Teton County, with a weighted average rising from 0.7 to 5.2, dropping its grade from B to F, the only county in the state to earn an F in that category.

The 2022 “State of the Air” found that year-round particle pollution levels in Wyoming were improved overall compared with last year’s report, with Albany County the only county reporting an increase. All counties earned passing grades. Cheyenne’s ranking improved by two spots in this year’s report, earning it the #1 cleanest city ranking in year-round particle pollution days. Casper’s ranking fell one spot from 5th to 6th in this year’s report. 

The report found that nationwide, nearly 9 million more people were impacted by deadly particle pollution than reported last year. It also shows more days with “very unhealthy” and “hazardous” air quality than ever before in the two-decade history of this report. Overall, more than 137 million Americans live in counties that had unhealthy levels of ozone or particle pollution. Communities of color are disproportionately exposed to unhealthy air. The report found that people of color were 61% more likely than white people to live in a county with a failing grade for at least one pollutant, and 3.6 times as likely to live in a county with a failing grade for all three pollutants.

The addition of 2020 data to the 2022 “State of the Air” report gives a first look at air quality trends during the COVID-19 pandemic. Regardless of the shutdowns in early 2020, there was no obvious improvement. 

The American Lung Association is calling on the Biden administration to strengthen the national limits on both short-term and year-round particulate matter air pollution. Stronger standards will educate the public about air pollution levels that threaten their health and drive the cleanup of polluting sources in communities across the country. See the full report results and sign the petition at

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