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The State of the Air 2020

Too many cities across the nation experienced more ozone and more particle pollution in 2016-2018. Many reached or tied their highest levels ever.

The "State of the Air" 2020 found that, in 2016-2018, more cities had high days of ozone and short-term particle pollution compared to 2015-2017 and many cities measured increased levels of year-round particle pollution.

2020 marks the 50th anniversary of the Clean Air Act, the landmark law that has driven dramatic improvements in air quality over its history. This is critical because far too many communities reported air pollution that still threatens health, and climate change impacts continue to threaten progress. Further, harmful revisions and setbacks to key protections currently in place or required under the Act threaten to make air quality even worse in parts of the country. "State of the Air" 2020 shows that we must not take the Clean Air Act for granted.

The "State of the Air" 2020 report shows that too many cities across the nation increased the number of days when particle pollution, often called "soot," soared to often record-breaking levels. More cities suffered from higher numbers of days when ground-level ozone, also known as "smog," reached unhealthy levels. Many cities saw their year-round levels of particle pollution increase as well.

The "State of the Air" 2020 report adds to the evidence that a changing climate is making it harder to protect human health. The three years covered in this report ranked among the five hottest years on record globally. High ozone days and spikes in particle pollution followed, putting millions more people at risk and adding challenges to the work cities are doing across the nation to clean up.

The 2020 report—the 21st annual release—uses the most recent quality-assured air pollution data, collected by the federal, state and local governments and tribes in 2016, 2017 and 2018. The "State of the Air" 2020 report looks at levels of ozone and particle pollution found at official monitoring sites across the United States in those years. For comparison, the "State of the Air" 2019 report covered data from 2015, 2016 and 2017.

The report examines fine particle pollution (particulate matter smaller than 2.5 microns in diameter, also known as PM2.5) in two separate ways: averaged year-round (annual average) and short-term levels (24-hour). For both ozone and short-term particle pollution, the analysis uses a weighted average number of days that allows recognition of places with higher levels of pollution. For the year-round particle pollution rankings, the report uses averages calculated and reported by the U.S. Environmental Protection Agency

Overall Trends

The "State of the Air" 2020 found that, in 2016-2018, millions more Americans were living in communities impacted by unhealthy levels of pollution in the form of more unhealthy ozone days, more particle pollution days and higher annual particle levels than in previous reports.

Nearly five in 10 people live where the air is unhealthy.

Nearly five in ten people—150 million Americans or approximately 45.8 percent of the population—live in counties with unhealthy ozone or particle pollution (at least one F). That represents an increase from the past three reports: it is higher than the 141.1 million in the 2019 report (covering 2015-2017), 133.9 million in the 2018 report (covering 2014-2016) and 125 million in the 2017 report (covering 2013-2015). More than 20.8 million people, or 6.4 percent of the population, live in the 14 counties that failed all three measures.

Los Angeles remains the city with the worst ozone pollution in the nation, as it has for 20 years of the 21-year history of the report. Bakersfield, CA, returned to the most polluted slot for year-round particle pollution, while Fresno-Madera-Hanford, CA, returned to its rank as the city with the worst short-term particle pollution.

This shows growing evidence that a changing climate is making it harder to protect human health. All three years ranked among the five hottest years in history, increasing high ozone days and widespread wildfires, putting millions more people at risk and adding challenges to the work cities are doing across the nation to clean up. Rollbacks of EPA cleanup rules and reduced Clean Air Act enforcement are further adding to these air quality challenges.

This marks the fourth report in a row that worsening air quality threatened the health of more people, despite other protective measures being in place. Climate change clearly drives the conditions that increase these pollutants. The nation must do more to address climate change and to protect communities from these growing risks to public health.

The Clean Air Act must remain intact and enforced to enable the nation to continue working to protect all Americans from the dangers of air pollution. As the nation celebrates the 50th anniversary of the Clean Air Act this year and the dramatic improvements in air quality over its history, everyone must ensure that the Clean Air Act's tools remain in place, funded and followed in order to protect the public.

The Lung Association will continue to champion the Clean Air Act and push for clean air for all, defending Americans against proposals to reverse and reduce protections in place and supporting new efforts to curb harmful pollution.

Comparison of Growth Areas and Emissions

Air pollution emissions have dropped steadily since 1970 thanks to the Clean Air Act. Source: U.S. EPA, Air Trends: Air Quality National Summary, 2019.

Did You Know?

  1. Nearly 5 out of 10 people live where the air they breathe earned an F in State of the Air 2020.
  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.
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