Many health issues are linked to air pollution, and the latest State of the Air report from the American Lung Association revealed that four in 10 Americans are living in areas with unhealthy levels. The study, however, also bears some good news for those living in the east.

The report measured two common types of air pollution - high particle pollution, or soot, and high ozone pollution, or smog - which are linked to cases of wheezing and coughing, asthma attacks, heart attacks and lung cancer. The good news is that many cities in the U.S. have actually shown improved conditions.

At least 13 metropolitan areas believed to have high levels of particle pollution, including Birmingham and Indianapolis, have significantly shown progress. The report said that this is due to the conscious shift in the use of cleaner fuel by consumers. Factories and power plants in the eastern part of America have also done their fair share of clean ups.

On the other hand, because of climate change, risks factors in areas in western states may bring more challenges, as high temperatures and drought can increase particle and ozone pollution. In a press release from the American Lung Association, the agency offers some steps to safeguard the air we breathe, knowing these challenges exist:

  • The EPA must update and uphold ozone standards and increase public awareness.
  • The Clean Air Act must be reviewed to provide tougher requirements that will reduce carbon pollution, and it must be effectively enforced.
  • The government must continue to fund the EPA so that it can proceed with monitoring.

"We have cleaner air today than we did 16 years ago - testament that the Clean Air Act works," said Harold P. Wimmer, National President and CEO of the American Lung Association. "Congress must allow the Clean Air Act to continue to protect our health, and ensure that the EPA and states can protect Americans from air pollution."

Here is the list of the most polluted cities in the U.S., according to the study:

Top 10 U.S. Cities Most Polluted by Short-term Particle Pollution (24-hour PM 2.5)

  1. Fresno-Madera, Calif.
  2. Bakersfield, Calif.
  3. Visalia-Porterville-Hanford, Calif.
  4. Modesto-Merced, Calif.
  5. Los Angeles-Long Beach, Calif.
  6. San Jose-San Francisco-Oakland, Calif.
  7. Salt Lake City-Provo-Orem, Utah
  8. Logan, Utah
  9. Fairbanks, Alaska
  10. Pittsburgh-New Castle-Weirton, Penn.-Ohio-West Va.


Top 10 U.S. Cities Most Polluted by Year-Round Particle Pollution (Annual PM 2.5)

Fresno-Madera, Calif.

Bakersfield, Calif.

Visalia-Porterville-Hanford, Calif.

Modesto-Merced, Calif.

Los Angeles-Long Beach, Calif.

El Centro, Calif.

San Jose-San Francisco-Oakland, Calif.

Cincinnati-Wilmington-Maysville, Ohio-Ky-Ind.

Pittsburgh-New Castle-Weirton, Penn.-Ohio-W.Va.

Cleveland-Akron-Canton, Ohio

Top 10 Most Ozone-Polluted Cities

Los Angeles-Long Beach, Calif.

Visalia-Porterville-Hanford, Calif.

Bakersfield, Calif.

Fresno-Madera, Calif.

Sacramento-Roseville, Calif.

Houston-The Woodlands, Texas

Dallas-Fort Worth, Texas-Okla.

Modesto-Merced, Calif.

Las Vegas-Henderson, Nev.-Ariz.

Phoenix-Mesa-Scottsdale, Ariz.