Despite years of progress in reducing man-made air pollution, overall air quality is declining, largely due to increased wildfires that are spreading smog across the nation. A new analysis reveals a concerning trend: improvements made in curbing conventional pollution sources are being offset by the growing impact of wildfires and extreme weather events.

American Lung Association Report: A “Distressing Reversal”

The American Lung Association’s (ALA) 2025 “State of the Air” report, released Wednesday, highlights a distressing reversal in air quality progress. The report, which analyzed air quality data collected in 2023 from the Environmental Protection Agency (EPA), indicates that gains made in reducing emissions from transportation, energy generation, and industrial processes are being undermined.

Years of triumphant cleanup of emissions from transportation, energy generation and industrial processes have contributed to falling ozone levels across much of the country since … 2000.
American Lung Association, 2025 State of the Air Report

Though, the report also cautions:

Regrettably, as was shown in 2023, one bad fire season has the potential to offset that progress, at least temporarily, creating new challenges for air pollution control efforts and putting the health of the communities affected at increased risk.
American Lung Association, 2025 State of the Air Report

chicago and California Hit Hard

The Chicago metropolitan area continues to struggle with air pollution, ranking 15th worst in the nation for smog levels, a decline from 17th in previous years. California dominates the list of most polluted cities, with nine of the top 25. Los Angeles holds the unfortunate top spot for ozone pollution.

The Science of Smog

Smog, or ozone air pollution, forms when air pollutants combine in sunlight. These pollutants are primarily produced by burning fossil fuels such as gasoline, diesel, coal, and natural gas. the chemical reactions triggered by sunlight intensify ozone pollution,making sunny days particularly problematic.

Climate Change: The Underlying Driver

The ALA report emphasizes that climate change is a meaningful factor behind the extreme weather events that exacerbate air pollution.Rising temperatures, prolonged droughts, and increased wildfires contribute to higher ozone levels and particle pollution.

Increases in high ozone days and spikes in particle pollution related to extreme heat, drought and wildfires are putting millions of people at risk and adding challenges to the work that states and cities are doing across the nation to clean up air pollution.
American Lung Association, 2025 State of the Air Report

Local Advocacy and Solutions

The report reinforces that we need to do more to curb air pollution, said Kristina Hamilton, Illinois advocacy director for the ALA. She highlighted transportation as a major pollution source in the Chicago area and emphasized the importance of reducing emissions, particularly in low-income communities near industrial centers.

If we can address diesel pollution, truck and freight traffic — and emissions from those sources — that would be tremendously helpful to the air pollution problem in the Chicago area.
Kristina Hamilton, Illinois Advocacy Director, American Lung Association

The ALA is advocating for state lawmakers to adopt stricter vehicle standards to reduce tailpipe emissions.

Particle Pollution: Another Cause for Concern

Chicago also faces challenges with particle pollution, ranking 19th in the nation for annual average pollution by fine particles, a worsening trend from previous years.

Key Findings from the Report

• 46% of Americans (156 million people) live in areas with failing grades for unhealthy levels of ozone or particle pollution, an increase of 25 million from last year and the highest in a decade.
• Illinois experienced one of the largest increases in ozone pollution between 2020-2022 and 2021-2023.
• Cook County received an “F” grade for high ozone days from 2021-2023, with 52 “orange” days and 6 “red” days of extremely poor air quality.
• The Peoria area ranked among the cleanest cities in America for short-term particle pollution, coming in at 23rd.