Inhaled air pollution among young children, especially during the first five years of life, is linked to structural changes in the brain as kids approach adolescence. This finding comes from a study conducted by ISGlobal, the Barcelona Institute for Global Health, and published in Environmental Pollution.
The research followed more than 3,500 children and is the first to track exposure from conception through the first eight and a half years of life. The most pronounced brain changes aligned with higher pollution exposure during those early years.
Anne-Claire Binter, a researcher at ISGlobal, notes that breathing polluted air in childhood affects the brain through its structural connections across different regions. The study highlights how early environmental factors shape neural networks.
Structural connectivity was assessed by examining white matter microstructure, a key indicator of typical brain development. Abnormal white matter patterns have been linked to various psychiatric conditions, including depressive symptoms, anxiety, and autism spectrum disorders.
Pollution’s impact on children’s brains is visually captured in images showing altered connectivity between brain regions. The accompanying photographs illustrate how environmental exposure may influence neural pathways.
Beyond overall connectivity, the researchers found a specific link between exposure to PM2.5 particles and the size of the putamen, a brain structure involved in movement, learning, and related processes. Higher PM2.5 exposure in the first two years of life correlated with a larger putamen volume.
According to Binter, a larger putamen has associations with certain psychiatric disorders, including schizophrenia, autism spectrum disorders, and obsessive-compulsive spectrum disorders. This finding adds another dimension to the brain development story under pollution exposure.
The study emphasizes periods of sensitivity to air pollution, using a finer timeline than earlier work. Instead of focusing on pregnancy trimesters or single childhood years, the analysis tracked exposure month by month, even up to eight weeks before conception, across the first five years of life. The research draws on atmospheric pollution data collected over that entire period.
The Generation R cohort from Rotterdam, Netherlands, provided the data, including 3,515 children—boys and girls—who were followed from early life to later childhood. The broad dataset allowed for a detailed look at how different exposure windows relate to later brain structure and function.
Nitrogen compounds and fine particles
To estimate each child’s exposure, daily levels of nitrogen dioxide NO2 and PM2.5 particles were tracked at their homes, up to eight and a half years after birth. When the participants reached ages nine to twelve, MRI scans were used to measure brain volumes and structural connectivity.
The NO2 and PM2.5 levels observed in the study surpassed the World Health Organization’s recommended limits for these pollutants. The results also suggest that adverse brain development could occur at pollutant levels below some established European Union standards.
Binter stresses that the brain’s vulnerability to air pollution extends beyond pregnancy into early childhood. The research team underscores the importance of ongoing measurements to understand any potential long-term effects of pollution exposure on brain development.
ISGlobal researchers, including Mònica Guxens, stress the need for continued follow-up of the children to monitor how early exposure might influence brain health later in life. The study contributes to a growing body of evidence that environmental factors play a role in neurodevelopment and associated psychiatric outcomes, underscoring the importance of clean air policies and protective health measures for children.