Despite increased urbanization and more cars on the road than ever before, the air quality in most of the U.S. better than it was just a few decades ago. Much of this improvement can be attributed to the federal Clean Air Act, as well as greater environmental awareness on the part of more individuals throughout the country.
But there are still cities in the United States that have probl ems with high air pollution levels. Keep in mind that air pollution takes many different forms, and a particular city might not have a significant problem with respect to one type of pollution, but provide an unhealthy environment with respect to a different type.
One of the primary air pollution offenders is ozone. Ozone (a molecule composed of 3 oxygen atoms) is beneficial when it’s in the upper atmosphere – the so-called “ozone layer” protects us from many of the sun’s harmful rays. But in the lower atmosphere, and in the air we breathe, ozone can be highly damaging.
The best authority on air pollution matters is the American lung Association. The most recent year’s analysis of cities that have the highest levels of dangerous ozone are as follows (note that most are not single cities, but metropolitan clusters of two or more cities):
- Los Angeles – Long Beach – Riverside, CA
- Bakersfield – Delano, CA
- Visalia – Porterville, CA
- Fresno – Madera, CA
- Sacramento – Arden-Arcade – Yuba City, CA
- Hanford – Corcoran, CA
- San Diego – Carlsbad-San Marcos, CA
- Houston – Baytown – Huntsville, TX
- Merced, CA
- Charlotte – Gastonia – Salisbury, NC-SC
Another type of pollution is so-called “particle pollution.” This is what most people think of when they hear the word “pollution.” Particle pollution comes from car exhaust, factory emissions, and dust. Unlike ozone, which is more of a problem during the summer, particle pollution problems can occur year round. The metropolitan areas that are most affected by year round particle pollution are:
- Bakersfield – Delano, CA
- Visalia – Porterville, CA
- Phoenix – Mesa – Glendale, AZ
- Los Angeles – Long Beach – Riverside, CA
- Hanford – Corcoran, CA
- Fresno – Madera, CA
- Pittsburgh – New Castle, PA
- Birmingham – Hoover – Cullman, AL
- Cincinnati – Middletown – Wilmington, OH-KY-IN
10. (tie) Modesto, CA
10. (tie) Louisville – Jefferson County – Elizabethtown – Scottsburg, KY-IN
Certain cities don’t have year round particle pollution, but do have shorter – sometimes seasonal – periods in which there are particle pollution problems. These metropolitan areas are:
- Bakersfield – Delano, CA
- Fresno – Madera, CA
- Pittsburgh – New Castle, PA
- Los Angeles – Long Beach – Riverside, CA
- Salt Lake City – Ogden – Clearfield, UT
- Provo – Orem, UT
- Visalia – Porterville, CA
- Birmingham – Hoover – Cullman, AL
9. (tie) Logan, UT-ID
9. (tie) Hanford – Corcoran, CA
9. (tie) Sacramento – Arden-Arcade – Yuba City, CA
Note that some cities are high on all three lists, and that most of these are in the west. If you live in or near these areas, make sure you take steps to protect yourself. At a minimum, you should pay attention to your local newscasts, many of which give warnings and status updates as to when pollution levels are dangerously high.