The results are in a study of 249 children of New York City women who wore backpack air monitors for 48 hours during the last few months of pregnancy. They lived in mostly low-income neighborhoods in northern Manhattan and the South Bronx. They had varying levels of exposure to typical kinds of urban air pollution, mostly from car, bus and truck exhaust.
At age 5, before starting school, the children were given IQ tests. Those exposed to the most pollution before birth scored on average four to five points lower than children with less exposure.
That’s a big enough difference that it could affect children’s performance in school, said Frederica Perera, the study’s lead author and director of the Columbia Center for Children’s Environmental Health.
In earlier research, involving some of the same children and others, Perera linked prenatal exposure to air pollution with genetic abnormalities at birth that could increase risks for cancer; smaller newborn head size and reduced birth weight. Her research team also has linked it with developmental delays at age 3 and with children’s asthma.
The researchers studied pollutants that can cross the placenta and are known scientifically as polycyclic aromatic hydrocarbons. Main sources include vehicle exhaust and factory emissions. Tobacco smoke is another source, but mothers in the study were nonsmokers.
The study does not mention smoke from forest fires. The subjects were exposed to urban air pollution, such as vehicle exhaust.
But they do point out that polycyclic aromatic hydrocarbons (PCH) can cross the placenta, and researchers HERE and HERE have identified PCH as being produced by forest fires. We don’t want to stir up a hornets nest, but if there is a link between PCH, forest fires, and low IQ scores, it could be an earth-shaking revelation. We can only hope that the PCH in forest fires is different from that found in vehicle exhaust, and is benign.