Nearly half of children in the United States are breathing dangerous levels of air pollution, according to a new report released Wednesday by the American Lung Association.

The organization's 27th annual air quality report evaluated pollution across the country by measuring levels of ground-level ozone, also known as smog, as well as year-round and short-term spikes in particle pollution, commonly referred to as soot. The analysis was based on quality-assured data collected between 2022 and 2024.

The findings come as the Trump administration has implemented what experts describe as an expansive rollback of environmental protections through the Environmental Protection Agency. Environmental health specialists have warned that these policy changes could worsen air quality conditions for children and other vulnerable populations.

Ground-level ozone forms when pollutants from vehicles, industrial facilities, and other sources react with sunlight and heat. Particle pollution consists of tiny particles that can penetrate deep into the lungs and enter the bloodstream, posing particular health risks to children whose respiratory systems are still developing.

The American Lung Association's annual State of the Air report has tracked air quality trends across the United States since 1999, providing data used by public health officials and policymakers to assess environmental health risks in communities nationwide.