

American Lung Association's 20th annual 'State of the Air' report sounds the alarm on worsened air quality driven by climate change, placing health and lives at risk

The American Lung Association's 2019 "State of the Air" report finds that an increasing number of Americans—more than 4 in 10—lived with unhealthy air quality, placing their health and lives at risk. The 20th annual air quality "report card" found that 141.1 million people lived in counties with unhealthful levels of either ozone or particle pollution, an increase of more than 7.2 million Americans since the last annual report. Eight cities recorded their highest number of days with unhealthy spikes in particle pollution since the nation began monitoring this pollutant 20 years ago. And the nation recorded more days with air quality considered hazardous, when air quality reached "emergency conditions"—Maroon on the air quality index—than ever before.

"The 20th annual 'State of the Air' report shows clear evidence of a disturbing trend in our air quality after years of making progress: In many areas of the United States, the air quality is worsening, at least in part because of wildfires and weather patterns fueled by climate change," said American Lung Association President and CEO Harold Wimmer. "This increase in unhealthy air is eye-opening, and points to the reality that the nation must do more to protect the public from serious, even life-threatening harm. There is no clearer sign that we are facing new challenges than air pollution levels that have broken records tracked for the past twenty years, and the fact that we had more days than ever before when monitored air quality reached hazardous levels for anyone to breathe."

The 2019 "State of the Air" report analyzed the three years with the most recent quality-assured data collected by states, cities, counties, tribes and federal agencies: 2015-2017. Notably, those three years were the hottest recorded in global history. When it comes to air quality, changing climate patterns fuel wildfires and lead to worsened ozone pollution. This degraded air quality threatens the health of Americans, especially those more vulnerable such as children, older adults and those living with a lung disease.

Each year, "State of the Air" reports on the two most widespread outdoor air pollutants, ozone pollution and particle pollution. Each is dangerous to public health and each can be lethal. The 2019 "State of the Air" report found that more than 20 million people lived in counties that had unhealthy levels of air quality in all categories.

Particle Pollution
Unhealthy particles in the air result from many sources, including wildfires, wood-burning devices, coal-fired power plants and diesel engines. Particle pollution can be deadly. Technically known as PM2.5, these microscopic particles lodge deep in the lungs and can enter the bloodstream, triggering asthma attacks, heart attacks and strokes, and can cause lung cancer.

The report has two grades for particle pollution: One for "short-term" particle pollution, or daily spikes in the pollutant, and one for the annual average or "year-round" level that represents the concentration of particles day-in and day-out in each location.

Short-Term Particle Pollution
More cities experienced days when there were spikes in particle pollution, with eight cities of the 25 most-polluted reaching their highest number of such days in the report's 20-year history: Fairbanks, Alaska; Salinas, CA; Santa Maria-Santa Barbara, CA; Missoula, Montana; Bismarck, ND; Bend-Pineville, OR; Spokane-Spokane Valley-Coeur d'Alene, WA-ID; and Yakima, Washington. Wildfires in 2017, especially in Montana, Washington and California, and woodsmoke from heating homes contributed to many of these dangerous spikes. Bakersfield, CA, remained the #1 most polluted city for short-term particle levels, as it has for eight of the past 10 reports. Overall, daily spikes in particle pollution are getting more frequent, and, in many cases, more severe, with four days reaching hazardous, Maroon alert levels in 2017, the highest number ever. Nationwide, more than 49.6 million people suffered those episodes of unhealthy spikes in particle pollution in the 76 counties where they lived.

Top 10 U.S. Cities Most Polluted by Short-Term Particle Pollution (24-hour PM2.5):

  1. Bakersfield, California
  2. Fresno-Madera-Hanford, California
  3. Fairbanks, Alaska
  4. San Jose-San Francisco-Oakland, California
  5. Missoula, Montana
  6. Yakima, Washington
  7. Los Angeles-Long Beach, California
  8. Salt Lake City-Provo-Orem, Utah
  9. Seattle-Tacoma, Washington
  10. Pittsburgh-New Castle-Weirton, Pennsylvania-Ohio-West Virginia

Year-Round Particle Pollution
More than 20.5 million people lived in counties with unhealthy levels of year-round particle pollution, which is more than in the last two annual "State of the Air" reports. Steps to clean up emissions that cause particle pollution helped reduce some averages. Meanwhile, major sources like agriculture, power plants and industrial sources still emit too much particulate matter, and wildfires in the western U.S. contributed to higher levels of particle pollution in several cities. Fresno-Madera-Hanford, CA, topped the list as most polluted by year-round particle levels in this year's report, tying its previous record for the highest level ever reached. 

Top 10 U.S. Cities Most Polluted by Year-Round Particle Pollution (Annual PM2.5):

  1. Fresno-Madera-Hanford, California
  2. Bakersfield, California
  3. Fairbanks, Alaska
  4. Visalia, California
  5. Los Angeles-Long Beach, California
  6. San Jose-San Francisco-Oakland, California
  7. Pittsburgh-New Castle-Weirton, Pennsylvania-Ohio-West Virginia
  8. El Centro, California
  9. Cleveland-Akron-Canton, Ohio
  10. Medford-Grants Pass, Oregon

 Ozone Pollution
Ozone pollution, often referred to as smog, harms lung health, essentially causing a sunburn of the lung. Specifically, inhaling ozone pollution can cause shortness of breath, trigger coughing and asthma attacks, and may shorten life. Warmer temperatures make ozone more likely to form and harder to clean up.

Significantly more people suffered unhealthy ozone pollution in the 2019 report than in the last two "State of the Air" reports. Approximately 134 million people lived where they experienced too many high ozone days, the highest number of people exposed since the 2016 report. This report shows the changing climate's impact on air quality, as ozone pollution worsened during the global record-breaking heat years tracked in the 2019 report.

Of the 10 most polluted cities for ozone, seven did worse than in last year's report, including many of the nation's largest metropolitan areas. Los Angeles's air quality worsened, and it remains #1 for most ozone-polluted city in the nation. Only Bakersfield, Fresno-Madera-Hanford and San Jose-San Francisco-Oakland had fewer days with high ozone than in the 2018 report.

Top 10 Most Ozone-Polluted Cities:

  1. Los Angeles-Long Beach, California
  2. Visalia, California
  3. Bakersfield, California
  4. Fresno-Madera-Hanford, California
  5. Sacramento-Roseville, California
  6. San Diego-Chula Vista-Carlsbad, California
  7. Phoenix-Mesa, Arizona
  8. San Jose-San Francisco-Oakland, California
  9. Houston-The Woodlands, Texas
  10. New York-Newark, New York–New Jersey-Connecticut-Pennsylvania

Cleanest Cities
The "State of the Air" also recognizes the nation's cleanest cities, and just like last year's report, only six cities qualified for that status. To rank as one of the nation's cleanest cities, a city must experience no high ozone or high particle pollution days and must rank among the 25 cities with the lowest year-round particle pollution levels during 2015-2017. 

Cleanest U.S. Cities (listed in alphabetical order)

  1. Bangor, Maine
  2. Burlington-South Burlington, Vermont
  3. Honolulu, Hawaii
  4. Lincoln-Beatrice, Nebraska
  5. Palm Bay-Melbourne-Titusville, Florida
  6. Wilmington, North Carolina

"Every American deserves to breathe healthy air that won't make them sick. The American Lung Association calls on the Administration and Congress to protect and prioritize Americans' health by taking urgent action to fight air pollution and address climate change," Wimmer said.

Learn more about the 20th anniversary of the "State of the Air" report at For media interested in speaking with an expert about lung health, healthy air, the health impacts of climate change and threats to air quality in metro regions nationwide, contact Allison MacMunn at the American Lung Association at [email protected] or 312-801-7628.

For more information, contact:

Allison MacMunn
[email protected]

, | Jun 24, 2021