Air today, trouble tomorrow.

Another prenatal precaution has been added to the running list: don't breathe! A number of studies have concluded exposure to air pollution, such as that found routinely in major American cities, can adversely affect fetal development (see "Womb Pollution?" in Brief, November/December 2004). In April, the Center for Children's Environmental Health at Columbia University released findings concluding that children exposed to combustion-related pollutants known as polycyclic aromatic hydrocarbons (PAH) in the womb are 2.9 times more likely to have cognitive development delays than those with less exposure.

The study followed 183 New York City children of non-smoking mothers and controlled for outside pollutants other than PAH. By age three, the children who were prenatally exposed to the highest levels of PAH scored 6.3 percent lower on cognitive tests than their lesser-exposed peers. "PAHs are widespread in urban environments largely as a result of fossil fuel combustions," the study states. "Fortunately, airborne PAH concentrations can be reduced through pollution controls, greater energy efficiency and alternative energy sources." CONTACT: Columbia Center for Children's Environmental Health, [phone], www.ccceh.org.