Meanwhile, Perera says that "aside from making sure that there are no other pollutant sources in the house such as tobacco smoke, families can proactively protect themselves by maintaining a clean home environment and good ventilation of cooking fumes, and by making sure that pregnant women and children consume healthy diets."
But, she noted, "as far as outdoor air exposure, that's a question for policymakers. I'm not a policy expert, but I would say fortunately that there are means at hand to address this problem. They include plans to reduce vehicle emissions, and to develop the technologies that would do so, along with policies that focus on energy efficiency and energy alternatives."
Michael Jerrett, an associate professor of environmental health sciences with the School of Public Health at University of California, Berkeley, expressed little surprise at the findings, and suggested that an association between in-utero PAH exposure and a lower IQ is "certainly plausible."
"Children exposed to prenatal or in-utero air pollution from traffic oftentimes have lower birth weights, somewhat smaller head circumferences, and a number of adverse outcomes," he noted. "There's certainly enough there to suggest an effect. And I think any one of those outcomes -- if they happen early enough in life -- can affect development through childhood and exert an impact on intelligence," Jerrett said.
"Of course you can't rule out other factors -- the school environment, the home environment, even the neighborhood environment -- that might affect IQ," Jerrett cautioned. "But certainly it is important for us to investigate this, and see what further study reveals."
For more on PAH exposure, visit the Agency for Toxic Substances and Disease Registry.
SOURCES: Frederica P. Perera, Ph.D., professor, department of environmental health sciences, Mailman School of Public Health, Columbia University, New York City, and director, Columbia Center for Children's Environmental Health; Michael Jerrett, Ph.D., associate professor, environmental health sciences, School of Public Health, University of California, Berkeley, and director, Doctor of Public Health Program; August 2009, Pediatrics