Key Findings

Learn the key findings and overall trends about air quality in states and cities in the American Lung Association's State of the Air report.

The “State of the Air” 2023 report finds that after decades of progress on cleaning up sources of air pollution, nearly 36% of Americans—119.6 million people—still live in places with failing grades for unhealthy levels of ozone or particle pollution. Overall, this is 17.6 million fewer people breathing unhealthy air compared to last year’s report. The improvement was seen in falling levels of ozone in many places around the country, the continuation of a positive trend that reflects the success of the Clean Air Act. However, the number of people living in counties with failing grades for daily spikes in deadly particle pollution was 63.7 million, the most ever reported under the current national standard.

more than one in three

More than 1 in 3 Americans live in places with unhealthy levels of air pollution.

The “State of the Air” report looks at two of the most widespread and dangerous air pollutants, fine particles and ozone. The air quality data used in the report are 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 daily and long-term measures of particle pollution and daily measures of ozone. Those values are also used to rank cities (metropolitan areas) and counties. This year’s report presents data from 2019, 2020 and 2021, the most recent quality-assured nationwide air pollution data publicly available. See About This Report for more detail about the methodology for data collection and analysis.

“State of the Air” 2023 is the 24th 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 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” 2023 ranked among the seven hottest years on record globally. High ozone days and spikes in particle pollution related to heat, drought and wildfires are putting millions of people at risk and adding challenges to the work that states and cities are doing across the nation to clean up air pollution.

Thermometer with arrow pointing up

Climate change is making the job of cleaning up the air more difficult.

The combination of policy-driven reductions in emissions on the one hand and climate change-fueled increases in pollution on the other hand is driving a widening disparity between air quality in eastern and western states, especially for particle pollution. When particle pollution was first added to the “State of the Air” report in 2004, 106 counties in 30 states got failing grades for daily spikes in particle pollution. Forty-four of those counties – fewer than half – were in 8 states west of the Rocky Mountains. In this year’s report, 111 counties in 19 states got Fs for this measure. All but 8 counties in Indiana, Michigan, Minnesota and Pennsylvania are in the West. A number of historically urban, industrialized eastern and midwestern states such as New Jersey, New York and Ohio, which dominated the list in the early years, are now getting all passing grades. A similar story can be told for annual particle pollution. In 2004, 20 of the 22 states with counties that got a failing grade were east of the Rockies. In 2023, all of the 17 failing counties were in 6 western states.

Circle graphic with 3.6X overlayed.

People of color are 3.7 times more likely than white people to live in a county with three failing grades.

Again this year, “State of the Air” finds that the burden of living with unhealthy air is not shared equally. Although people of color are 41% of the overall population of the U.S., they are 54% of the nearly 120 million people living in counties with at least one failing grade. And in the counties with the worst air quality that get failing grades for all three pollution measures, 72% of the 18 million residents affected are people of color, compared to the 28% who are white.

In “State of the Air” 2023, Bakersfield, California displaced Fresno, California as the metropolitan area with the worst short-term particle pollution while Bakersfield continued in the most-polluted slot for year-round particle pollution, tied this year with Visalia, California. Los Angeles remains the city with the worst ozone pollution in the nation, as it has for all but one of the 24 years tracked by the “State of the Air” report.

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 counties for ozone and particle pollution ranked.
Learn more

Cleanest Places to Live

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

Recommendations for Action

We need action at every level to clean up air pollution and address climate change.
Learn more

Did You Know?

  1. More than one in three Americans live where the air they breathe earned an F in “State of the Air” 2023.
  2. Nearly 120 million people live in counties that received an F for either ozone or particle pollution in “State of the Air” 2023.
  3. More than 18 million people live in counties that got an F for all three air pollution measures in “State of the Air” 2023.
  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 with 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 forecast 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 whose smoke spreads dangerous particle pollution.
  17. Policymakers at every level of government must take steps to clean the air their residents breathe.
  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 over 50 years.
Get more facts »
Take Action
  • State of the Air print report