State of the Air 2026 Report

The Clean Air Act requires the U.S. Environmental Protection Agency (EPA) to set healthbased limits, called National Ambient Air Quality Standards (NAAQS), for six dangerous outdoor air pollutants: particulate matter, ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide and lead. “State of the Air” looks at two of the most widespread and dangerous pollutants from this group: fine particulate matter and ozone.

The NAAQS identify what is considered a safe level of each pollutant to breathe, based on the most recent health and medical science, including an adequate margin of safety for those most at risk. These standards require states and local governments to take steps to reduce emissions to meet (“attain”) the standards. The standards also serve to alert families with children, seniors, individuals with lung or heart conditions, and others about dangerous air pollution levels through color-coded air quality alerts. This enables people to take necessary precautions to minimize their exposure. Under the Clean Air Act, the standards must be based solely on what is needed to protect health and must be periodically updated as the science evolves.

Setting national health-based air quality standards, and requiring states whose air violates these standards to enact plans to clean up their air pollution problems, have been a great benefit to the public health of the nation. Between when the Clean Air Act was passed in 1970 and 2020, the combined emissions of six key air pollutants fell by 78%, according to EPA. But as “State of the Air” 2026 shows, millions of people in this country are still breathing unhealthy air—and hard-fought progress is at grave risk.