The "State of the Air" 2021 report finds that despite some nationwide progress on cleaning up air pollution, more than 40% of Americans—over 135 million people—are living in places with unhealthy levels of ozone or particle pollution. The burden of living with unhealthy air is not shared equally. People of color are over three times more likely to be breathing the most polluted air than white people.

Circle graphic with 3X overlayed.

People of color are over three times more likely to be breathing the most polluted air than white people.

The "State of the Air" report looks at two of the most widespread and dangerous air pollutants, ozone and fine particulate matter. The air quality data used in the report is collected at official monitoring sites across the United States by the federal, state, local and tribal governments. The Lung Association calculates values reflecting the air pollution problem and assigns grades for ozone and daily and long-term measures of particle pollution. Those values are also used to rank cities (metropolitan areas) and counties. This year's report presents data from 2017, 2018 and 2019, the most recent quality-assured nationwide air pollution data publicly available.

"State of the Air" 2021 is the 22nd edition of this annual report, which was first published in 2000. From the beginning, the findings in "State of the Air" have reflected the successes of the now-50-year-old Clean Air Act, as emissions from transportation, power plants and manufacturing have been reduced. In recent years, however, the findings of the report have added to the evidence that a changing climate is making it harder to protect human health.

The three years covered by “State of the Air” 2021 ranked among the six hottest years on record globally. High ozone days and spikes in particle pollution, related to extreme heat and wildfires, are putting millions more people at risk and adding challenges to the work states and cities are doing across the nation to clean up air pollution.

The COVID-19 pandemic has driven home to the world the preciousness of healthy lungs.1 New research shows that exposure to elevated levels of air pollution is linked to worse health outcomes from COVID-19, including higher death rates. As the nation continues to respond to the pandemic, reducing air pollution is critical for respiratory health now and in the future. The Lung Association will continue to champion the Clean Air Act and push for clean air, health equity and environmental justice for all.

More than four in ten Americans (41.1%–more than 135 million Americans) are living in the 217 counties across the nation with monitors that are capturing unhealthy levels ozone or particle pollution. This is 14.8 million fewer people breathing unhealthy air compared to last year's report, mostly from improved levels of ozone pollution. However, the threat of deadly particulate matter air pollution continues to worsen with each new edition of "State of the Air." This year’s report finds an increase of close to 1.1 million people living in areas with unhealthy levels of short-term particle pollution compared to last year's report.

Circle graphic with 3X overlayed.

More than 4 in 10 Americans live in places with unhealthy levels of air pollution.

Close to 20.7 million people, or 6.3% of Americans, live in the 13 counties that failed all three measures. Of these 20.7 million people, 14 million are people of color. People of color were 61% more likely than white people to live in a county with a failing grade for at least one pollutant, and over three times as likely to live in a county with a failing grade for all three pollutants.

Los Angeles remains the city with the worst ozone pollution in the nation, as it has for all but one of the 22 years tracked by the "State of the Air" report. Fairbanks, Alaska earned the unfortunate distinction of being the metropolitan area with the worst short-term particle pollution for the first time. And Bakersfield, California returned to the most polluted slot for year-round particle pollution for the second year in a row.

More Findings

Ozone Trends

Exposure to unhealthy levels of ozone air pollution continues to make breathing difficult for millions of Americans.
Learn more

Short-Term Particle Pollution Trends

Many cities reached their highest number of days with unhealthy levels of particle pollution ever reported.
Learn more

Year-Round Particle Pollution Trends

More than 20.9 million people live where year-round particle pollution levels are worse than the national air quality limit.
Learn more

Populations at Risk

Some groups of people are especially vulnerable to illness and death from exposure to unhealthy levels of air pollution.
Learn more

Most Polluted Places

See the 25 most polluted cities and counties for ozone and particle pollution ranked.
Learn more

Cleanest Places to Live

Five cities rank on all three cleanest cities lists for ozone, year-round and short-term particle pollution.
Learn more

What Needs to Be Done

The nation has an opportunity to curb climate change, clean up air pollution and promote health equity all at the same time.
Learn more

Did You Know?

  1. More than four in ten Americans live where the air they breathe earned an F in “State of the Air” 2021.
  2. More than 135 million people live in counties that received an F for either ozone or particle pollution in “State of the Air” 2021.
  3. Close to 20.7 million people live in counties that got an F for all three air pollution measures in “State of the Air” 2021.
  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.
Get more facts » 
Take Action
  1. The “State of the Air” 2021 covers the years 2017, 2018 and 2019 and does not reflect any changes in activity patterns and air quality that may have resulted from the COVID-19 pandemic in 2020. That data will not be available until next year. More information about the relationship between air pollution and COVID-19 can be found in the Health Impacts of Air Pollution section.