Exposure to pollutants from fossil fuel combustion during pregnancy was linked to children with more attention and behavioral problems, U.S. researchers said. Lead author Frederica Perera, director of the Columbia Center for Children\'s Environmental Health at the Mailman School of Public Health at Columbia University, said the study tracked the children of 253 non?smoking inner-city women who gave birth from 1999 to 2006. The mothers were exposed to polycyclic aromatic hydrocarbons released into air during incomplete combustion of fossil fuel such as diesel, gasoline, coal and other organic material, Perera said. The researchers monitored air concentrations of polycyclic aromatic hydrocarbons and a polycyclic aromatic hydrocarbon-specific biomarker of exposure measured in maternal and umbilical cord blood, Perera said. The mothers completed a detailed assessment of their child\'s behavior -- including symptoms of anxiety, depression or attention problems. The study published in the journal Environmental Health Perspectives found high prenatal polycyclic aromatic hydrocarbons exposure, whether characterized by personal air monitoring or maternal and newborn cord adducts, was significantly associated with symptoms of anxiety/depression and attention problems. \"The results are of concern because attention problems and anxiety and depression have been shown to affect peer relationships and academic performance,\" Perera said in a statement.