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  • ALA State of the Air 2021: 7 Things to Know

    Highlights to help you stay air aware in your city.

    Adult carry child on shoulders through the woods wearing rain jackets.

    • Each year, the State of the Air details information on how and where air pollution is doing damage in the United States. Here, we give some background on the report and share seven key takeaways from this year’s findings.

      What is the State of the Air report?

      Since 2000, the American Lung Association (ALA) has released its annual report on the state of air quality in different cities and regions nationwide. It focuses specifically on ozone and fine particulate matter, the two most harmful and common pollutants. This year’s report analyzes U.S. data from 2017, 2018 and 2019, and grades overall air quality based on three measures: ozone levels, year-round particle pollution and short-term (24-hour) particle pollution.

      1. More than 4 out of 10 Americans live in a region where pollution frequently makes outdoor air unhealthy.

      More than 135 million Americans live in cities where ozone and fine particulate matter were measured at unhealthy levels. This is an improvement over last year’s number, mostly from improved levels of ozone pollution. However, nearly 1.1 million more people are living in areas with unhealthy levels of short-term particle pollution compared to last year's report. According to the ALA, frequently breathing in ozone and particle pollution can lead to lung inflammation, asthma attacks and increase the risk of lung cancer or complications from COVID-19.¹

      2. Higher global temperatures and natural disasters contribute to increased air pollution.

      The three years covered by this year’s report were ranked among the six hottest years on record. Extreme heat can cause a spike in ozone levels²—and natural disasters like wildfires release all sorts of unhealthy particulate matter into the air.¹

      3. California is home to 10 of the 25 most ozone-polluted cities in the country.

      Los Angeles continues to remain the worst city for ozone pollution in the nation. The city has held that position for all, except one, of the report’s 22-year history. California cities, Bakersfield and Visalia, follow with the second- and third-highest year-round ozone levels.³ Other cities in the top 10 include Phoenix-Mesa, Arizona; Salt Lake City, Utah; and Denver-Aurora, Colorado.

      4. More than 54 million Americans live in cities that earned an F grade in short-term (24-hour) particle pollution.

      In order to pass the daily particle pollution measure, a city must have fewer than 3.2 days with unhealthy, very unhealthy or hazardous air.³ For the first time, Fairbanks, Alaska, was ranked the worst city in the country for short-term particle pollution. It recorded its highest-ever average number of days with spikes in particle levels. Significant wildfires in 2019 also resulted in three days where outdoor air quality in Fairbanks spiked to hazardous—the highest level in the Air Quality Index.⁴ Keep in mind, things like wood stove use, older diesel vehicles and equipment, and industrial sources also contribute to particle pollution.

      5. Your city can be affected by pollution created in other areas of the country.

      Although western U.S. cities tend to have the highest levels of ozone pollution, eastern cities can still experience bad air days due to transported pollution. Upwinds can carry ozone and particle pollution from the Midwest up to the Northeast. Fairfield, Connecticut, has the highest ozone pollution in the Eastern half of the country, in part because of pollutants coming in from other states.²

      6. Poor air quality disproportionately affects people of color, people experiencing poverty and people with underlying health conditions.

      People of color are over three times more likely than white people to breathe the most polluted air. Nearly 2.8 million people in poverty and 1.3 million children with asthma live in cities that failed all three air pollution measures.⁵

      7. The top five cleanest cities in the U.S. had zero days for high ozone or particle pollution.

      The five cleanest U.S. cities are Burlington-South Burlington-Barre, Vermont; Charlottesville, South Carolina; Elmira-Corning, New York; Urban Honolulu, Hawaii; and Wilmington, North Carolina.

      See how your city stacks up here.


      1. https://www.lung.org/research/sota/air-quality-facts

      2. https://www.lung.org/research/sota/key-findings/ozone-pollution

      3. https://www.lung.org/research/sota/about-the-report/methodology

      4. https://www.lung.org/research/sota/key-findings/short-term-particle-pollution

      5. https://www.lung.org/research/sota/key-findings/people-at-risk