What U.S. city has the worst air quality?
Matthew Cannon
Updated on January 17, 2026
Los Angeles air pollution
Los Angeles has the most contaminated air in the country. With a population of roughly over 10 million, the Los Angeles area is a large basin with the Pacific Ocean to the west and bounded prominently on the north and east by the San Gabriel and San Bernardino mountains.Which US cities have the best air quality?
Best cities in year-round particle pollution:
- Cheyenne, Wyoming.
- Wilmington, North Carolina.
- Urban Honolulu, Hawaii.
- Kahului-Wailuku-Lahaina, Hawaii.
- Bangor, Maine.
- Casper, Wyoming.
- Bellingham, Washington.
- Bismarck, North Dakota, Elmira-Corning, New York, Sioux Falls, South Dakota and St. George, Utah.
Where is the cleanest air in the USA?
Hawaii. Hawaii has an air quality index of 21.2, the cleanest average air in the U.S. This is well in the good air quality index range.What is the cleanest state in America?
The cleanest states
- 1. California Cleanliness Score: 7.36. California is the cleanest state overall with a cleanliness score of 7.36. ...
- HawaiiCleanliness Score: 6.94. Hawaii claims second place with a cleanliness score of 6.94. ...
- WashingtonCleanliness Score: 6.40.
Why is California the most polluted state?
The combination of three main factors are the cause of notable unhealthy levels of air pollution in California: the activities of over 39 million people, a mountainous terrain that traps pollution, and a warm climate that helps form ozone and other pollutants.Top 10 worst cities for Smog! Air quality losers
What is the dirtiest city in California?
1. Fresno, Calif. comprised of Fresno-Madera metro area ranks #1 dirties city in America for its power-punch combo of groundwater polluted by agriculture and air quality.Is New York really polluted?
A Hot Spot for NOx PollutionNew York is also the worst offender in the country when it comes to NOx emissions from residential and commercial buildings—a distinction driven primarily by combustion emissions in New York City buildings.
Where is the healthiest air in California?
The American Lung Association also keeps track of which cities have the least air pollution. Only one California city ranked among the list of top 25 cities with the least amount of particle pollution: Salinas in Monterey County.What's the unhealthiest state in America?
1. Mississippi. Mississippi has consistently been the country's most unhealthy state for several years. While Mississippi has a low drug death rate and low prevalence of excessive drinking, it falls behind in many other categories.Where is the most toxic place in America?
The title for most toxic location in the United States goes to a remote, and perhaps surprising location. According to the EPA's Toxics Release Inventory (TRI), Kotzebue, Alaska, a city of 3,500 residents located 30 miles north of the Arctic Circle takes that dubious honor.What are the top 10 dirtiest cities in America?
- Los Angeles. Pollution score: 66.48 (out of 100) Shutterstock.
- Salt Lake City. Pollution score: 61.93. Shutterstock.
- Detroit. Pollution score: 58.48. ...
- New York. Pollution score: 57.68. ...
- Phoenix, Ariz. Pollution score: 56.31. ...
- Houston. Pollution score: 56.23. ...
- Philadelphia. Pollution score: 53.72. ...
- Las Vegas. Pollution score: 52.79.