This website uses cookies. By continuing you are agreeing to our privacy policy.

Wyoming Receives Mixed Grades for Air Quality, Finds 2019 ‘State of the Air’ Report

Cheyenne and Casper have some of the cleanest air in the U.S.

(April 24, 2019) - CHEYENNE, Wyo.

For more information please contact:

Holly Harvey
[email protected]
(206) 512-3292

The American Lung Association’s 2019 “State of the Air” report found that Wyoming received mixed grades for its air quality. While Casper and Cheyenne were rated two of the cleanest air quality areas in the country, Sublette, Campbell, and Sheridan all received “D” grades.

This year’s report covers the most recent quality-assured data available collected by states, cities, counties, tribes and federal agencies in 2015-2017. Notably, those three years were the hottest recorded in global history.

Casper and Cheyenne are both ranked as cleanest cities in the nation for both ozone pollution and year-round particle pollution. Both Natrona and Laramie County counties slipped a letter grade and received a “B” and “C” respectively. Sublette County received a “D” grade for ozone; Campbell and Sheridan received a “D” grade for particle pollution.

“Though Casper and Cheyenne are highlighted in our report as having clean air, there are some counties in Wyoming with air quality concerns,” said Carrie Nyssen, Senior Director of Advocacy for the American Lung Association in Wyoming. “Right now, more than four in 10 Americans are living with unhealthy air, and we’re heading in the wrong direction when it comes to protecting public health and people’s lives.”

Each year the “State of the Air” provides a report card on the two most widespread outdoor air pollutants, ozone pollution, also known as smog, and particle pollution, also called soot. The report analyzes particle pollution in two ways: through average annual particle pollution levels and short-term spikes in particle pollution. Both ozone and particle pollution are dangerous to public health and can increase the risk of premature death and other serious health effects such as lung cancer, asthma attacks, cardiovascular damage, and developmental and reproductive harm

Cheyenne experienced only one day of high ozone pollution during this data set. This year’s report showed that ozone levels increased in most cities nationwide, in large part due to the record-breaking global heat experienced in the three years tracked in the report.

While the report examined data from 2015-2017, this 20th annual report online provides information on air pollution trends back to the first report. Learn more about Wyoming’s rankings, as well as air quality across the nation, in the 2019 “State of the Air” report at For media interested in speaking with an expert about lung health, healthy air, and threats to air quality, contact Holly Harvey at [email protected] or 206-512-3292.

2019 Cleanest Cities

Cleanest for Ozone Pollution (zero unhealthy air days - all counties)

  • Anchorage, AK
  • Bellingham, WA
  • Casper, WY
  • Fairbanks, AK
  • Idaho Falls-Rexburg-Blackfoot, ID
  • Honolulu, HI

Cleanest Cities for Year-Round Particle Pollution (cities with the lowest annual levels)
 1. Cheyenne, WY (tie)
 1. Honolulu, HI (tie)
1. Kahului-Wailuku-Lahaina, HI (tie)
 4. Casper, WY (tie)
4. St. George, UT (tie)
6. Elmira-Corning, NY
7. Duluth, MN-WI (tie)
7. Pueblo-Canon City, CO (tie)
9. Bismarck, ND (tie)
10.  Bellingham, WA (tie)
10. Syracuse-Auburn, NY (tie)



About the American Lung Association

The American Lung Association is the leading organization working to save lives by improving lung health and preventing lung disease, through research, education and advocacy. The work of the American Lung Association is focused on four strategic imperatives: to defeat lung cancer; to improve the air we breathe; to reduce the burden of lung disease on individuals and their families; and to eliminate tobacco use and tobacco-related diseases. For more information about the American Lung Association, a holder of the coveted 4-star rating from Charity Navigator and a Gold-Level GuideStar Member, or to support the work it does, call 1-800-LUNGUSA (1-800-586-4872) or visit:

Red button with telephone
Ask An Expert

Questions about your lung health? Need help finding healthcare? Call 1-800-LUNGUSA.

Get help
Red button of two hand prints
We need your generous support

Make a difference by delivering research, education and advocacy to those impacted by lung disease.

Button of turquoise LUNG FORCE swirl

LUNG FORCE unites women and their loved ones across the country to stand together in the fight against lung cancer.

Get involved
Join the fight for healthy lungs and healthy air.
Donate Now.