A recent study published in Pediatrics, July 2009, disclosed an adverse relationship between high levels of polycyclic aromatic hydrocarbons (PAH) found in air pollution and IQ scores of children tested at age 5.
PAH’s are pollutants released by the air during combustion of fossil fuels, tobacco, and other organic matter. Urban minorities tend to have excessive exposure to these compounds. This is especially concerning for pregnant women because of the potential effects these pollutants may have on the fetal brain and nervous system.
Studies in the past have shown that PAH’s from diesel exhaust decreased learning in mice. Fetal growth reduction, including reduction in fetal weight, decreased head circumference, reduced mental development scores, and developmental delays were also found with PAH exposure. This new study now shows an association between high PAH levels and IQ score.
Two hundred and forty nine children were followed from nonsmoking, black and Dominican women age 18 to 35 in the South Bronx. Approximately 56% of the children had high exposure to PAH as measured by monitors during the third trimester of pregnancy. After testing IQ scores at age 5, these children had lower full scale IQ scores and lower verbal scores. The lower scores are of concern since they are predictive of subsequent academic performance in elementary school. The mechanism of how PAH’s affect the fetal brain are unknown.
Communities should strictly enforce greater energy efficiency and control air contamination. In addition, there should be continued search for alternative energy sources to control exposure to PAH and prevent harmful effects on the neurodevelopment of children.
