The study assembled data from over 2,700 primary school children between the ages of 7 and 10. Researchers measured the memory and attentiveness abilities in these children, and repeated the every three months for one year.
The study found that children going to school in high-traffic areas and exposed to a greater amount of air pollutants are slower to develop cognitively and achieve lower scores in memory tests.
Previous studies looked on the effect of air pollution on heart and lungs have also been documented, but its effect on the brain, in this case on the developing brain, has not been widely studied.
Most relevant in the study were the differences in brain development occurred with relationship memory. Children tested in low-pollution areas were found to improve their working memory over the year by 11.5 percent while those children in high-pollution areas in the same age-range improved their memory during that same year by just 7.4 percent.
Scientists considered factors such as commuting time to school, amount of green space at their schools, the level of education achieved by their parents and smoking at home. Yet, the negative influence of pollution and cognitive brain development and memory remained unchanged.
Researchers examined the level of burning fossil fuels, carbon, nitrogen dioxide and level of ultrafine particles in both the playgrounds of each school and in classrooms.
Dr. Jordi Sunyer from the Barcelona research group said the results indicate air pollutants have “very robust, consistent effects” on cognition and memory in children.
The study is published in PLOS Medicine.