The babies of women living in high air pollution neighborhoods may have lower IQs.
A study followed low-income pregnant women in the South Bronx and upper Manhattan. The women wore monitors during the last months of pregnancy. They lived in areas that had high pollution from cars, buses and trucks.
Before starting school, the children took IQ tests. The children most exposed to air pollution scored lower than children with lower exposure did. The difference of four or five points may affect schoolwork.
Experts say the differences do not mean that children will not learn to read and write. It shows that air pollution may harm children as much as lead does.
The research may explain why these children do not do well in school.
Earlier research showed that air pollution could increase the risk of cancer, lower birth weight and asthma.
Researchers plan to continuing monitoring and testing the children. They want to know if school performance is affected over a long time.
Experts said this research was important. They said there should be more studies.