Air pollution can seriously impair emotional and self-regulation in unborn children. New research reveals that expectant moms exposed to common air pollutant are significantly more likely to give birth to children who have trouble regulating thoughts, emotions and behavior.

Researchers from Columbia University looked at how early life exposure to a common air pollutant called polycyclic aromatic hydrocarbons (PAH). Sources that produce PAH include car emissions, coal burning, and tobacco smoke.

The latest study involved data from 462 mother-child pairs living in New York City. Researchers took blood samples from pregnant women and tested children's emotional and self-regulation at ages three, four, five, seven, nine and 11.

After comparing maternal blood samples to results from child tests and found that children of mothers who had higher exposure to polycyclic aromatic hydrocarbons during pregnancy scored significantly worse on the Deficient Emotional Self-Regulation Scale at ages nine and 11 compared to those whose moms had lower polycyclic aromatic hydrocarbons exposure.

"We detected a significant interaction of exposure with time, in which the developmental trajectory of self-regulatory capacity was delayed in the exposed children. Multiple linear regression revealed a positive association between presence of polycyclic aromatic hydrocarbons - DNA adducts and problems with social competence, level of dysregulation and problems with social competence, and evidence that self-regulation mediates the association of prenatal exposure to PAH with social competence," researchers wrote in the study.

"These data suggest that prenatal exposure to polycyclic aromatic hydrocarbons produces long-lasting effects on self-regulatory capacities across early and middle childhood, and that these deficits point to emerging social problems with real-world consequences for high-risk adolescent behaviors in this minority urban cohort," they added.

Researchers said the latest study is important because it suggests that everyday air pollutants can predispose unborn children to a host of mental issues with regulating thoughts, emotions and behavior later in life. Previous studies have linked prenatal exposure to attention-deficit/hyperactivity disorder, anxiety, depression, inattention, and behavioral disorders.

"This study indicates that prenatal exposure to air pollution impacts development of self-regulation and as such may underlie the development of many childhood psychopathologies that derive from deficits in self-regulation, such as attention-deficit/hyperactivity disorder, obsessive compulsive disorder, substance use disorders, and eating disorders," explained Margolis.

The findings are published in the Journal of Child Psychology and Psychiatry.