Year-Round Particle Pollution Trends

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Some 20.3 million people live in the 21 counties where year-round particle pollution levels do not meet the national air quality standard, and that receive a failing grade in “State of the Air” 2022. This is slightly fewer people living in counties with unhealthy levels of year-round particle pollution than in the past three years’ reports, but higher than in reports published in 2017 and 2018. 

By its nature, the year-round measure of average particle pollution is not as volatile as the daily measure. Changes over time may look smaller, but because they represent recurring exposures over many days and weeks, small differences can have a big impact on public health. The 25 most polluted cities for year-round particle pollution (which actually includes 26 cities this year, because of a tie for 25th place) continued last year’s trend of worsening slightly, by an average of 0.2 micrograms per cubic meter (from 12.0 to 12.2).  

Eighteen cities suffered worse year-round levels during 2018-2020 than in last year’s report, and four reported their worst ever: Medford-Grants Pass and Bend-Prineville, Oregon; Redding-Red Bluff, California; and Yakima, Washington. In contrast, six of the most polluted cities had lower year-round levels, including Detroit and Pittsburgh, which reported their lowest levels ever. Pittsburgh, a city long notorious for its industrial pollution, showed the most improvement of any of the cities on this list, lowering its average annual particle pollution level by 1.3 micrograms per cubic meter, and achieving a passing grade for the first time.  

New on the worst 25 list this year were Chico, California; Bend-Prineville, Oregon; Yakima, Washington; and Augusta, Georgia. Cleveland, Missoula and New York all improved enough to leave the list. 

Unlike the worst 25 cities for the daily measure of particle pollution, the worst 25 cities for long-term particle pollution were more distributed around the country. In addition to cities most affected by western wildfires, cities with high power plant emissions as well as local industrial and mobile sources continued to show up on this list. These included Cincinnati, Indianapolis, Pittsburgh, Detroit, Philadelphia, Chicago, Houston, St. Louis, Augusta and Shreveport. 

For year-round average levels of fine particles, all cities but the ten most polluted meet the current national air quality standards and get a passing grade in “State of the Air." However, evidence shows that no threshold exists for harmful effects from particle pollution, even below the official standard. The Lung Association continues to advocate for standards more protective of health for fine particle pollution. See Recommendations for Action. 

Did You Know?

  1. More than four in ten Americans live where the air they breathe earned an F in “State of the Air” 2022.
  2. More than 137 million people live in counties that received an F for either ozone or particle pollution in “State of the Air” 2022.
  3. Close to 19.8 million people live in counties that got an F for all three air pollution measures in “State of the Air” 2022.
  4. Breathing ozone irritates the lungs, resulting in inflammation—as if there were a bad sunburn within the lungs.
  5. Breathing in particle pollution can increase the risk of lung cancer.
  6. Particle pollution can cause early death and heart attacks, strokes and emergency room visits.
  7. Particles in air pollution can be smaller than 1/30th the diameter of a human hair. When you inhale them, they are small enough to get past the body's natural defenses.
  8. Ozone and particle pollution are both linked to increased risk of lower birth weight in newborns.
  9. If you live or work near a busy highway, traffic pollution may put you at greater risk of harm.
  10. People who work or exercise outside face increased risk from the effects of air pollution.
  11. Millions of people are especially vulnerable to the effects of air pollution, including children, older adults and people with lung diseases such as asthma.
  12. People of color and those earning lower incomes are disproportionately affected by air pollution that puts them at higher risk for illness.
  13. Air pollution is a serious health threat. It can trigger asthma attacks, harm lung development in children, and even be deadly.
  14. You can protect yourself by checking the air quality forecasts in your community and avoiding exercising or working outdoors when unhealthy air is expected.
  15. Climate change enhances conditions for ozone pollution to form and makes it harder clean up communities where ozone levels are high.
  16. Climate change increases the risk of wildfires that spread particle pollution in the smoke.
  17. The Biden Administration has made bold commitments to improve air quality, especially in communities that have faced disproportionate levels of pollution. The Lung Association is advocating to make sure they are realized.
  18. The nation has the Clean Air Act to thank for decades of improvements in air quality. This landmark law has driven pollution reduction for 50 years.
  19. Cutting air pollution through the Clean Air Act was projected to prevent over 230,000 deaths and save nearly $2 trillion in 2020 alone.
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