The Clean Air Act requires the U.S. Environmental Protection Agency (EPA) to set health-based limits, called National Ambient Air Quality Standards (NAAQS), for six dangerous outdoor air pollutants: particulate matter, ozone, nitrogen oxides, sulfur dioxide, carbon monoxide and lead. “State of the Air” looks at two of the most widespread and dangerous pollutants from this group, fine particulate matter and ozone.  

The NAAQS identify what is considered a safe level of each pollutant to breathe, based on the most recent health and medical science, including an adequate margin of safety for those most at risk. These standards alert the public when pollution levels place Americans’ health at risk and require states and local governments to take steps to reduce emissions to attain the standards. The standards are also used to inform families with children, seniors, people with lung or heart disease and others when air pollution levels are dangerous through color-coded air quality alerts, so they can take steps to limit their exposure. Under the Clean Air Act, the standards must be based solely on what is needed to protect health, and must be periodically updated as the science evolves. EPA is currently reviewing both the particulate matter and ozone standards; future editions of “State of the Air” will reflect any revisions to the standards. 

Setting national health-based standards and requiring states that violate the standards to enact plans to clean up their air pollution problems have been a great benefit to the public health of the nation. Since the Clean Air Act was passed in 1970, emissions of these outdoor air pollutants, including ozone and particle pollution, have fallen by 78%, according to EPA. But as “State of the Air” 2023 shows, millions of Americans are still breathing unhealthy air. 

In the year 2000, the American Lung Association launched its annual “State of the Air” report to provide the public with easy-to-understand information about the quality of the air in their local communities based on the credible data and sound science that EPA is required to use to set the air quality standards.  

For the first several years, “State of the Air” focused solely on ozone pollution and included data for five populations at increased risk – children, older adults, children with asthma, adults with asthma and people with emphysema. In 2004, changes to the air quality standards and the deployment of air pollution monitoring enabled the addition of short-term and year-round fine particle pollution to the report. Over time, accumulating scientific evidence has shown significant health harms from both ozone and particle pollution among other groups of vulnerable individuals. “State of the Air” has accommodated this new information by gradually adding populations-at-risk categories to its reporting. “State of the Air” 2023 now includes data for 10 vulnerable groups. 

Since its inception, “State of the Air” has been tremendously successful in raising awareness about particle pollution and ozone, two of the most dangerous and pervasive air pollutants nationwide. The American Lung Association is proud and grateful that the public, the media, clean air advocates and decision-makers have used this report every day, year after year, to call attention to the work that remains to be done to protect the health of all Americans from the threat of air pollution. 

We write and release “State of the Air” every year to make information on air quality and health clear and accessible to everyone. We show the progress each community has made and how much more needs to be done to achieve healthy air. In this report, you’ll find information on local air quality nationwide. You’ll also find the latest roundup of the research on how air pollution affects health. With these tools, you can help keep your lungs and your family’s lungs safer from unhealthy air.

This report also includes ideas for how you can become a champion for clean air. First, we have suggestions for concrete actions you can take to reduce your own contributions to air pollution and climate change. And second, we invite you to take advocacy action with the American Lung Association. Our report includes policy recommendations for every level of government. Your voice is powerful, and when you tell your leaders that your lungs depend on stronger limits on air pollution, you make a compelling case. Please share your story and add your name to our petition – and then, take the next step. Reach out to your representatives at every level of government, share the “State of the Air” results for your community, and call on them to take action to protect public health.

For long-time Los Angeles area residents, poor air quality isn’t always top of mind, with smog and bad air days a regular occurrence.

Lee M. has lived in Southern California for 12 years. The change in air quality is noticeable when away, such as during his visits to Portland, Oregon.

“When you go to other places, you realize it’s not as fresh as it could be,” he says. “There’s that feeling when you get off the train in Portland – it’s green, I can breathe and it doesn’t smell like cars.”

Lee considers air quality when choosing where to live. He avoids living near freeways due to noise and air concerns but still has to regularly clean his porch of soot and dust, especially when winds blow wildfire smoke into the region.

“Clean air makes for a better place to be.”

Lee M.
West Hollywood, California


Did You Know?

  1. More than 4 out of 10 people live where the air they breathe earned an F in State of the Air 2021.
  2. 150 million people live in counties that received an F for either ozone or particle pollution in State of the Air 2020.
  3. More than 20.8 million people live in counties that got an F for all three air pollution measures in State of the Air 2020.
  4. Breathing ozone irritates the lungs, resulting in something like a bad sunburn within the lungs.
  5. Breathing in particle pollution can increase the risk of lung cancer, according to the World Health Organization.
  6. Particle pollution can also cause early death and heart attacks, strokes and emergency room visits for people with asthma and cardiovascular disease.
  7. Particles are 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. Do you live near, or work on or near a busy highway? Pollution from the traffic 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 infants, older adults and people with lung diseases like asthma.
  12. People of color and those earning lower incomes are often disproportionately affected by air pollution that put them at higher risk for illnesses.
  13. Air pollution is a serious health threat. It can trigger asthma attacks, harm lung development in children, and can even be deadly.
  14. You can protect your family by checking the air quality forecasts in your community and avoiding exercising or working outdoors when the unhealthy air is expected.
  15. Climate change enhances conditions for ozone to form and makes it harder to keep ozone from forming.
  16. Climate change increases the risk of wildfires that spread particle pollution and ozone in the smoke.
  17. This Administration is trying to roll back or create loopholes in core healthy air protections under the Clean Air Act. The Lung Association opposes these actions that will add pollution to the air we breathe.
  18. Cutting air pollution through the Clean Air Act will prevent at least 230,000 deaths and save $2 trillion annually by 2020.
Get more facts » 
Take Action

Page last updated: April 18, 2023