Air pollution can reduce a child's IQ

NEW YORK, July 21 (UPI) -- Pre-natal exposure to environmental pollutants -- polycyclic aromatic hydrocarbons -- may adversely affect a child's IQ, U.S. researchers say.

Researchers at the Columbia Center for Children's Environmental Health at the Mailman School of Public Health in New York say polycyclic aromatic hydrocarbons are chemicals released into the air from the burning of coal, diesel, oil and gas, or other organic substances such as tobacco.

In cities, motor vehicles are a major source of polycyclic aromatic hydrocarbons, the researchers say.

The study, published in the August issue of Pediatrics, finds that children exposed to high levels of polycyclic aromatic hydrocarbons in New York had full scale and verbal IQ scores that were 4.31 and 4.67 points lower, respectively, than those of less exposed children. High polycyclic aromatic hydrocarbons levels were defined as above the median of 2.26 nanograms per cubic meter.

"These findings are of concern because these decreases in IQ could be educationally meaningful in terms of school performance," lead author Frederica Perera says in a statement. "The good news is that we have seen a decline in air pollution exposure in our cohort since 1998."