World (Development News) – January 2, 2026

Scientists at Oregon Health & Science University have found that exposure to common air pollutants is associated with thinning of the cerebral cortex in two key brain regions during adolescence.

According to the journal Environmental Research, researchers analyzed data from nearly 11,000 participants enrolled in the largest long-term U.S. study on children’s brain development, known as the Adolescent Brain Cognitive Development (ABCD) Study.

The research team compared levels of exposure to fine particulate matter, nitrogen dioxide, and ozone with changes in cortical thickness among participants aged 9–10 and then followed them over subsequent years.

The results showed that exposure even to relatively low concentrations of air pollutants—levels currently considered acceptable under existing standards—was linked to accelerated cortical thinning.

These changes were observed in the frontal and temporal lobes, regions responsible for attention, language, emotional regulation, and social behavior.

The researchers explained that this effect does not occur abruptly, but rather accumulates slowly over time.

This means it may not cause immediate symptoms, yet it could influence the trajectory of brain development and increase the likelihood of cognitive and emotional difficulties later in life.

The study also found that early adolescence, a period marked by intense growth of neural connections, is particularly sensitive to such effects.

During this stage, the brain is highly vulnerable to external factors, foremost among them the quality of the air being inhaled.

The researchers concluded that these findings underscore the need to reconsider current air quality standards.

They also stressed the importance of placing greater emphasis on environmental risks within healthcare policies aimed at children and adolescents.