Study tracks pollution and brain development

Columbia University researchers followed over 1,100 children and mothers in Northern Manhattan and the South Bronx from 1998 to 2020, measuring how air pollution affected cognitive development.

Three pollutants tracked before birth

Researchers measured prenatal exposure to fine particulate matter (PM2.5), nitrogen dioxide, and polycyclic aromatic hydrocarbons, then tested children's cognitive skills at ages one, two, and three.

Pollution dropped dramatically over 22 years

Between 1998 and 2016, PM2.5 exposure fell 51% and nitrogen dioxide fell 48%. Polycyclic aromatic hydrocarbon exposure dropped 66% between 1998 and 2020.

Cognitive scores improved with cleaner air

As pollution levels fell, children's test scores on memory, problem-solving, speech, and language comprehension increased, particularly at ages two and three.

“We tested cognitive processing including memory and sensory perception, problem-solving such as matching shapes, stacking blocks and communication.”

Higher pollution linked to lower scores

Children exposed to more PM2.5, nitrogen dioxide, and polycyclic aromatic hydrocarbons during pregnancy had lower cognitive scores at ages one, two, and three.

Other factors also improved over time

Tobacco smoke exposure at home fell from 34% to 18%, and maternal high school graduation rates increased. These changes make it hard to prove cleaner air alone caused better scores.

“We cannot conclude that contemporary levels of air pollution are safe for the neurodevelopment of all children.”

More research needed on air quality

Researchers say the findings show an association between cleaner air and better cognitive outcomes, but further studies are needed to understand this relationship and inform climate policies.

“We need more studies such as ours to increase public awareness of the value of clean air and climate policies.”