The State of the Air report is an annual publication of the American Lung Association (ALA) that ranks cities and counties based on their levels of air pollution. The following is a list of the cleanest cities for air pollution from that report, based on the annual PM2.5 concentration, a measure of the yearly concentration of particles in the air that are less than 2.5 micrometers in size (PM2.5), which are thought to be the most harmful to human health. The ALA used the Environmental Protection Agency’s database to obtain the data, calculated the concentration of a pollutant, and ranked cities based on the EPA’s determination of the number of days that violated the national ambient air quality standard for annual PM2.5 of 15 µg/m³. The list below represents the cities with the best annual PM2.5 measures over the years 2004-2006 followed in parentheses by the total population that inhabits each area. Note that mostly small and medium-sized cities make the list.

The top 10 cities with the cleanest air in the U.S. are:

1. Cheyenne, WY (85,384)
2. Santa Fe-Espanola, NM (183,356)
3. Honolulu, HI (909,863)
4. Great Falls, MT (79,385)
5. Farmington, NM 126,473
6. Tucson, AZ (946,362)
7. Bismarck, ND (101,138)
8. Flagstaff, AZ 124,953
9. Anchorage, AK (359,180)
10. Salinas, CA (410,206)

To find out more about diseases caused by air pollution, join the Healia Health Community for Lung Diseases or the Healia Health Community for Heart Diseases.

Related blog posts: Study Finds Cleaner Air Lengthens American Lives by Nearly Five Months

        The Top 10 Most Polluted Cities in America

_{Source: American Lung Association, State of the Air 2008, Table 2. http://www.stateoftheair.org/2008/key-findings/SOTA08_Table2.pdf}