An under-researched field exploring the intersection of pollution and mental health is gaining momentum as evidence mounts that environmental pollutants damage every organ in our bodies—including our brains.

This guide explores the emerging science, and offers solutions aimed at better supporting mental health in the face of these environmental challenges.

According to the American Lung Association’s 2021 State of the Air report, about four in 10 U.S. residents live in counties with unhealthy levels of air pollution. But what counts as “unhealthy” is based only on how pollution affects physical, not mental, health.

Scientists have known for a long time that air pollution damages the lungs, leading to conditions like asthma and lung cancer, and that it can damage the heart as well. Only much later, researchers discovered that air pollution also causes changes in the brain that increase the risks of mental illness, dementia, Alzheimer’s, and learning problems. Even small increases in air pollution have been linked to depression and anxiety.