New ‘State of the Air’ Report Finds Chicagoland Residents Are Breathing Some of the Most Polluted Air in the Country

The air quality in Greater Chicago has worsened according to the American Lung Association’s 2025 “State of the Air” report, released today. Residents are being exposed to more unhealthy ozone smog and particle pollution the report finds. Chicagoland is ranked 15th worst in the nation for ozone pollution with 20.3 unhealthy days per year and received an F grade. The metro area also received a failing grade for year round particle pollution and is ranked 13rd worst in the nation.

The report also found that nearly half of the U.S. population, 156 million people, live in areas with unhealthy levels of air pollution. Researchers add extreme heat and wildfires contributed to the worsening air quality across much of the country.

The Lung Association’s 26th annual “State of the Air” report grades exposure to unhealthy levels of ozone air pollution and particle pollution over a three-year period (2021-2023). The report looks at the latest quality-assured air quality data from 2021-2023. Findings for the Chicago metro area include:

• Ground-level Ozone Pollution in the Chicago-Naperville, IL-IN-WI metro area:
  • National Ranking: 15th worst out of 228 (17th worst in 2024 report)
  • Number of Unhealthy Days Per Year: 20.3 days per year (15.3 days per year in 2024 report)
  • Grade: F, Cook County, IL worst in metro area (F in 2024 report)
• Short-term Particle Pollution in the Chicago-Naperville, IL-IN-WI metro area:
  • National Ranking: 53rd worst out of 223 (73rd worst in 2024 report)
  • Number of Unhealthy Days Per Year: 3.7 days per year (1.3 days per year in 2024 report)
  • Grade: F, Porter County, IN worst in metro-area (C in 2024 report)
• Year-Round Average Level of Particle Pollution in the Chicago-Naperville, IL-IN-WI metro area:
  • National Ranking: 13th worst in the nation (22nd worst in 2024 report)
  • Grade: Failing grade, pollution levels above the federal standard

Ozone smog and particle pollution are widespread and can impact anyone’s health. Both pollutants can cause premature death and other serious health effects such as asthma attacks, heart attacks and strokes, preterm births and impaired cognitive functioning later in life. Particle pollution can also cause lung cancer.

“Unfortunately, too many people in the Chicagoland area continue to live with unhealthy levels of ozone and particle pollution. This air pollution is a threat to human health at every stage of life – from increasing the risk of premature birth and low birth weight babies to causing or worsening lung disease,” said Kristina Hamilton, Advocacy Director for the American Lung Association. “We urge Illinois policymakers to take action to improve our air quality, including adopting clean vehicle standards and we are calling on everyone to support the incredibly important work of the U.S. Environmental Protection Agency (EPA).”

Air quality in most other areas of the state also significantly worsened since last year’s report.

Highlights include: The Springfield metro area ranked 40th worst for ozone and 77th worst for year-round particle pollution; the Rockford metro area’s grade for particle pollution fell from an A to a D; and the Peoria metro area’s grade for ozone pollution fell from a B to an F while it received an A grade for short-term particle pollution, up from a B.

On a national level, the “State of the Air” report found that 156 million people in the U.S. (46%) live in an area that received a failing grade for at least one measure of air pollution. 42.5 million people live in areas with failing grades for all three measures. The report also found that a person of color in the U.S. is more than twice as likely as a white individual to live in a community with a failing grade on all three pollution measures. Notably, Hispanic individuals are nearly three times as likely as white individuals to live in a community with three failing grades.

In Illinois, the Lung Association is urging the state’s Pollution Control Board to adopt key clean vehicle standards—the Advanced Clean Trucks, Heavy-Duty Low-NOx Omnibus and Advanced Clean Cars II—because of the air quality and lung health benefits these standards will provide. Additionally, the organization is urging the Illinois General Assembly to pass the Powering Up Illinois Act (HB 5610 / SB 3794), which modernizes Illinois’ planning process for distribution electricity infrastructure to account for air quality standards.

The Lung Association is calling on everyone to support the U.S. Environmental Protection Agency. The EPA is essential to protecting people’s health from ozone and particle pollution. Join the American Lung Association in advocating to protect EPA’s expert staff and lifesaving programs. See the full report results and take action at Lung.org/sota.

The “State of the Air” report relies on data from air quality monitors managed by state, local and Tribal air pollution control authorities in counties across the U.S. The rankings are based on the worst county in the area’s average number of unhealthy days.

Get involved and help the American Lung Association’s mission at the Fight For Air Climb – Chicago on Sunday June 22nd at Soldier Field. Learn more at FightForAirClimb.org/Chicago.

Media Resources

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