Kids who live in neighborhoods with heavy traffic pollution have lower IQ's and lower scores on intelligence and memory tests than those who breathe cleaner air.
So says a new study from the Harvard School of Public Health.
The study showed that the more heavily exposed children were to black carbon, the lower their scores on several intelligence tests. On average, their IQ was 3.4 points lower.
Researchers say the effect was similar to kids who have been exposed to lead, or those whose mothers smoked during pregnancy.
Dr. Shakira Franco Suglia, leader of the Harvard team, says traffic pollution may cause harmful effects by causing inflammation, and oxidative damage to the brain.
Dr. Suglia says more studies into pollution's impact are a must for all ages, including investigating potential links to Alzheimer's or Parkinson's disease.
