New Report: Denver, Fort Collins Named Among the Most Polluted Cities

Lung Association “State of the Air” Report reveals that Coloradans faced more days of poor air quality

The 2022 “State of the Air” report, released today by the American Lung Association, finds that Denver’s and Fort Collins’ rankings were worse for some of the most harmful and widespread types of air pollution: particle pollution and ozone. Residents in the Denver metro area experienced more days of unhealthy levels of ozone and particle pollution. Compared to last year’s report, Denver’s rankings were worse in all three categories: ground-level ozone pollution, year-round particle pollution, and short-term particle pollution. Fort Collins residents experienced a slight improvement with fewer unhealthy ozone days, but more unhealthy days of short-term particle pollution spikes. Both Denver (7th) and Fort Collins (18th) ranked among the 25 worst cities in the country for ozone pollution. 

Grand Junction ranked among the country’s cleanest cities, making the lists for both short-term and year-round particle pollution. Colorado Springs made the cleanest cities list for only year-round particle pollution, while Pueblo made the cleanest cities list for short-term 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

“The levels of ozone and particle pollution seen in many areas of Colorado can harm the health of all of our residents, 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 Colorado
Compared to the 2021 report, Denver experienced more unhealthy days of high ozone in this year’s report. “State of the Air 2022” ranked Denver as the 7th most polluted city for ozone pollution, one spot worse compared to the city’s 8th place ranking in 2021. For the first time since 2016, every county in the Denver region earned a failing grade. Adams County recorded the region’s steepest decline, falling from B to F in this category.

On average, Fort Collins experienced slightly fewer unhealthy days of high ozone in this year’s report, although “State of the Air 2022” still ranked Fort Collins among the nation’s most polluted cities for ozone pollution (18th) – one spot better compared to the city’s 17th place ranking in 2021. 

El Paso County’s grade for ozone pollution fell from D in last year’s report to F in this year’s report, with residents experiencing more unhealthy days of high ozone. Jefferson County once again recorded Colorado’s worst levels of ozone, while Archuleta County and Delta County each earned A’s for recording zero unhealthy days of high ozone.

Particle Pollution in Colorado
The report also tracked short-term spikes in particle pollution, which can be extremely dangerous and even lethal. The air quality impacts from the 2020 wildfires are clear in this year’s report, as the 2022 report includes data from 2018-2020. Short-term particle pollution levels in the Denver metro area worsened in this year’s report compared to last year’s report, ranking 31st among the most-polluted cities nationally in that category. In fact, the Denver area recorded its worst-ever levels of short-term particle pollution. Boulder County reported the highest number of unhealthy particle pollution days in the region, and Arapahoe County was the only county in the region to improve over last year’s grade, going from B to A in this year’s report. 

Short-term particle pollution in Fort Collins also increased to its worst levels ever. The city’s ranking among the most polluted went from 50th in last year’s report to 30th in this year’s report. Prior to the 2016 State of the Air report, Fort Collins had ranked among the nation’s cleanest cities in this category.

Weld County was also among the counties experiencing a significant increase in number of unhealthy short-term particle pollution days, with a grade falling from D in last year’s report to F in this year’s report.

The 2022 “State of the Air” found that year-round particle pollution levels in Colorado were slightly worse overall than in last year’s report, but all counties earned passing grades. 

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

For more information, contact:

James A. Martinez
(312) 445-2501
[email protected]

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