2024 ‘State of the Air’ Report Reveals Most ‘Hazardous’ Air Quality Days in 25 Years (2024)

CHICAGO | April 24, 2024

The American Lung Association’s new “State of the Air” report reveals that spikes in deadly particle pollution are the most severe they’ve been in the history of the report. According to the new report, people in the U.S. experienced the most days with “very unhealthy” and “hazardous” air quality due to particle pollution in 25 years. In total, the report finds that 131 million people (39%) are living in areas with unhealthy levels of air pollution.

The Lung Association’s 25th annual “State of the Air” report grades exposure to unhealthy levels of ground-level ozone air pollution (also known as smog) and short-term spikes and annual average of particle pollution (also known as soot) over a three-year period. This year’s report includes the most recent quality-assured air quality data from 2020-2022 and is updated to reflect the new annual particle pollution standard that the U.S. Environmental Protection Agency (EPA) finalized in February 2024.

“We have seen impressive progress in cleaning up air pollution over the last 25 years, thanks in large part to the Clean Air Act. However, when we started this report, our team never imagined that 25 years in the future, more than 130 million people would still be breathing unhealthy air,” said Harold Wimmer, President and CEO of the American Lung Association. “Climate change is causing more dangerous air pollution. Every day that there are unhealthy levels of ozone or particle pollution means that someone – a child, grandparent, uncle or mother – struggles to breathe. We must do more to ensure everyone has clean air.”

The report found that nearly 4 in 10 people live in an area that received a failing grade for at least one measure of air pollution. 43.9 million people live in areas with failing grades for all three measures. People of color are disproportionately exposed to unhealthy air and are also more likely to be living with one or more chronic conditions that make them especially vulnerable to air pollution, including asthma, diabetes and heart disease. The report found that a person of color in the U.S. is 2.3 times more likely than a white individual to live in a community with a failing grade on all three air pollution measures.

Particle Pollution

Fine particulate matter air pollution, also known as PM2.5, particle pollution or soot, can be deadly. These particles come from wildfires, wood-burning stoves, coal-fired power plants, diesel engines and other sources. These microscopic particles can trigger asthma attacks, heart attacks and strokes, and cause lung cancer.

The report has two grades for particle pollution: one for “short-term” particle pollution, or daily spikes, and one for the annual average “year-round” level that represents the concentration of particles in each location.

Short-Term Particle Pollution

Spikes in particle pollution continue to impact communities in many parts of the country. The report finds that 65 million people lived in counties that experienced unhealthy spikes in particle pollution, the highest number reported in 14 years. In the three years covered by this report, individuals in the U.S. experienced the highest number of days when particle pollution reached “very unhealthy” and “hazardous” levels in the 25 years of reporting the “State of the Air.”

Short term particle pollution spikes are a clear example of the impacts that climate change is having on health. Changing weather patterns are driving more frequent and severe wildfires, which are delivering dangerous levels of particle pollution to more communities.

Top 5 Cities Most Polluted by Short-Term Particle Pollution:

  1. Bakersfield, CA
  2. Fresno-Madera-Hanford, CA
  3. Fairbanks, AK
  4. Eugene-Springfield, OR
  5. Visalia, CA

Year-Round Particle Pollution

More than 90.7 million people live in one of the 119 counties where year-round particle pollution levels are worse than the new national air quality limit. This is the largest number in the report’s history. It is an increase of 71.9 million compared to last year’s report. This increase is partly due to EPA’s new, stricter National Ambient Air Quality Standard for the annual measure of fine particulate matter, finalized in February. The standard now better reflects the science on health harm and shows that millions of people are living in areas that have unhealthy levels of annual particle pollution.

Top 5 Cities Most Polluted by Year-Round Particle Pollution:

  1. Bakersfield, CA
  2. Visalia, CA
  3. Fresno-Madera-Hanford, CA
  4. Eugene-Springfield, OR
  5. San Jose-San Francisco-Oakland, CA

Ozone Pollution

Ground-level ozone pollution is a powerful respiratory irritant whose effects have been likened to a sunburn of the lungs. Inhaling ozone can cause shortness of breath, trigger coughing and asthma attacks and may shorten life. Warmer temperatures driven by climate change make ozone more likely to form and harder to clean up.

Although there were exceptions, ozone pollution has generally improved across the nation. 2.4 million fewer people lived in areas with unhealthy ozone pollution compared to last year’s report, but more than 100 million people (nearly 30%) still live with unhealthy ozone pollution. The “State of the Air” report has seen a dramatic improvement in ozone pollution over the last 25 years. The first “State of the Air,” released in May 2000, reported that 72% of people in the U.S. who lived in counties with ozone monitors had unhealthy levels of ozone pollution.

Top 5 Cities Most Polluted by Ozone Pollution:

  1. Los Angeles-Long Beach, CA
  2. Visalia, CA
  3. Bakersfield, CA
  4. Fresno-Madera-Hanford, CA
  5. Phoenix-Mesa, AZ

Cleanest Cities

The report also recognizes the nation’s cleanest cities. To make the cleanest list for all three measures, a city must experience no high ozone or particle pollution days and rank among the 25 cities with the lowest year-round particle pollution levels.

Cleanest U.S. Cities (listed in alphabetical order):

  • Bangor, ME
  • Johnson City-Kingsport-Bristol, TN-VA
  • Lincoln-Beatrice, NE
  • Urban Honolulu, HI
  • Wilmington, NC

The 2024 “State of the Air” reports on air quality during the three years (2020-2022) of the COVID-19 pandemic. While many people speculated that the changes in behaviors during the pandemic, such as working from home, would result in improved air quality, this report shows that poor air quality continued to impact millions of people during those years. Notably, freight and goods movement on heavy-duty trucks, by rail and at ports increased significantly in some regions, adding to increased pollution burdens. In addition, wildfire smoke presented a major and increasing threat to lung health during these years.

EPA recently finalized new air pollution rules that will help clean up particle pollution and address climate change, such as the updated particle pollution standards, a rule to place stricter limits on tailpipe emissions from new cars and a rule to clean up truck pollution. Now, the Lung Association is urging EPA to set long-overdue stronger national limits on ozone pollution. Stronger limits would help people protect themselves and drive cleanup of polluting sources across the country.

See the full report results and sign the petition at Lung.org/SOTA.


About the American Lung Association

The American Lung Association is the leading organization working to save lives by improving lung health and preventing lung disease through education, advocacy and research. The work of the American Lung Association is focused on four strategic imperatives: to defeat lung cancer; to champion clean air for all; to improve the quality of life for those with lung disease and their families; and to create a tobacco-free future. For more information about the American Lung Association, which has a 4-star rating from Charity Navigator and is a Platinum-Level GuideStar Member, call 1-800-LUNGUSA (1-800-586-4872) or visit:Lung.org.To support the work of the American Lung Association, find a local event atLung.org/events.

2024 ‘State of the Air’ Report Reveals Most ‘Hazardous’ Air Quality Days in 25 Years (2024)


Has air quality in the United States generally improved over the past 30 years? ›

Over the past 30 years, there have been substantial reductions in air pollutant emissions and concentrations despite large increases in total U.S. population, vehicle miles traveled (VMT), energy consumption, and gross domestic product (GDP).

What is the state of the air report? ›

"State of the Air" is the American Lung Association's annual national air quality "report card." It uses the most recent air pollution data, compiled by the U.S. Environmental Protection Agency (EPA), for the two most widespread types of pollution—ozone (smog) and particle pollution (PM2.5, also known as soot).

How bad will air pollution be in 2050? ›

By 2050, outdoor air pollution particulate matter and ground-level ozone is projected to become the top cause of environmentally related deaths worldwide. A study showed that with no change in emissions by 2050, 1,126,000 premature mortalities are expected each year due to ozone8.

What has happened to air quality in the US over the past 30 years? ›

Air quality has improved significantly in recent decades following passage of the Clean Air Act in 1970. However, there are still many areas of the country where the public is exposed to unhealthy levels of air pollutants and sensitive ecosystems are damaged by air pollution.

Which state has the best air quality year round? ›

The state of Hawaii boasts the cleanest average air in the entire U.S., at an AQI of 21.2. Even Hawaii's biggest city, Honolulu, ranks on the cleanest cities for lists for ozone, short-term particle pollution, and year-round particle pollution.

Where in the US has the worst air quality? ›

Los Angeles air pollution. Los Angeles has the most contaminated air in the country. With a population of roughly over 10 million, the Los Angeles area is a large basin with the Pacific Ocean to the west and bounded prominently on the north and east by the San Gabriel and San Bernardino mountains.

What is the most air polluted state in the US? ›

1. California

California is the most polluted state in the US. Six of the most polluted cities are located in California, with Fresno-Madera and Bakersfield being the two areas with the highest levels of particulate pollution. The worst ozone levels can be found in Los Angeles.

What country has the best air quality? ›

The seven countries that met the safe guideline of five micrograms per cubic metre of air (µg/m3) or less were Australia, Estonia, Finland, Grenada, Iceland, Mauritius and New Zealand. Puerto Rico, Bermuda and French Polynesia also fell within safe levels.

Why has the air quality been so bad? ›

In addition to weather, extreme pollution events such as wildfires can cause significant spikes in L.A. air quality. Such pollution events have become increasingly common in the area over the last few decades as a result of anthropogenic climate change.

What will happen to Earth in 2024? ›

That team predicts a 58% chance that this year will be warmer than last year, and that 2024 will almost certainly be the hottest or second-hottest year on record.

What will be uninhabitable by 2050? ›

The most vulnerable areas include South Asia, the Persian Gulf, and the Red Sea by around 2050; and Eastern China, parts of Southeast Asia, and Brazil by 2070. A prototype wet-bulb globe temperature forecast map for the Raleigh-Durham, North Carolina region.

How long until the earth is too polluted? ›

The current rate of greenhouse gas pollution is so high that Earth has about 11 years to rein in emissions if countries want to avoid the worst damage from climate change in the future, a new study concludes.

What pollutes the air the most? ›

Vehicle emissions, fuel oils and natural gas to heat homes, by-products of manufacturing and power generation, particularly coal-fueled power plants, and fumes from chemical production are the primary sources of human-made air pollution.

What year will the air be too polluted? ›

By 2050, outdoor air pollution (particulate matter and ground-level ozone) is projected to become the top cause of environmentally related deaths worldwide (see figure below).

Is air quality still declining in the United States? ›

Air Quality Trends Show Clean Air Progress

Nationally, concentrations of air pollutants have dropped significantly since 1990: Carbon Monoxide (CO) 8-Hour, 79%

Has air quality improved in the US? ›

National air quality has improved since the 1990s, but many challenges remain in protecting public health and the environment from air quality problems.

Is air quality better now than it was 40 years ago? ›

Air Quality Trends

The table below show that air quality based on concentrations of the common pollutants has improved nationally since 1980.

How has the EPA improved air quality over the last 30 years? ›

Lead Removed from Gasoline

Motor vehicles were once the major contributor of lead emissions. EPA began to phase out lead in gasoline starting in the 1970's and leaded gasoline was fully prohibited after 1995. As a result, levels of lead in the air decreased by 94 percent between 1980 and 1999.

Has air quality improved since 1990? ›

Globally, we see that in recent decades, the death rates from total air pollution have declined: since 1990, death rates have nearly halved. But, as we see from the breakdown, this decline has been primarily driven by improvements in indoor air pollution.


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