New Report Shows Colorado Air Isn’t As Clean

When it comes to Colorado, you would think our air is some of the cleanest in the nation. Partly due to our elevation. When you venture into the mountains, you cannot help but breathe deeply. Not only because the air is thinner, but it feels cleaner.

Colorado’s Air Quality May Surprise You

The American Lung Association has released the State of the Air report for 2026, and Colorado's ranking might not be what you would expect. The breakdown of the cities that have the most polluted air includes three categories: Ozone, Short-term Particle Pollution, and Year-round Particle Pollution.

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Two Colorado metro areas ranked in the ozone pollution categories. The Fort Collins-Loveland metro area ranked 18th, and the Denver-Aurora-Greeley metro area ranked 8th on the list for the most polluted cities for ozone.

A Strange Metro Area Grouping

What I find to be the oddity in these two rankings is that Greeley is lumped in with the Denver Metro Area and not the Fort Collins-Loveland metro area. The Denver-Aurora-Greeley metro area ranked the 8th worst for high ozone days, with 226 days out of the year.

As for the Denver-Aurora-Greeley metro areas, the 24-hour particle pollution ranking was 106th out of 224 metropolotian areas, and the annual pollution ranking was 114th out of 211 metro areas.

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When it comes to the Fort Collins-Loveland metro areas, the annual particle pollution ranking was 181 out of 211 metropolotian areas. Where the Fort Collins-Loveland metro area really took top honors was in the 24-hour particle pollution ranking. Fort Collins-Loveland was ranked the best out of 224 metropolotian areas.

Learn More About the Report

Learn more about the American Lung Association State of the Air report for 2026 at lung.org.