A new study conducted by Columbia University has linked Attention Deficit Hyperactivity Disorder (ADHD) with air pollution in densely populated areas of New York City.

The research was gathered by the Columbia Center for Children’s Environmental Health at the Mailman School of Public Health, and has revealed a possible link between PAH, or polycyclic aromatic hydrocarbons, and children developing ADHD.

PAH are urban air pollutants emitted from diesel trucks and buses, oil-based heaters and power plants. The study suggests that prenatal exposure to PAH can lead to behavioral problems associated with ADHD at age nine, and those that exposed to pollutants are more likely to develop symptoms.

Between 1998 and 2006, Columbia researchers monitored 233 nonsmoking pregnant women. Blood samples from the umbilical cords were taken after delivery, and the children were assessed for signs of ADHD annually. Symptoms of ADHD include inattention, hyperactivity, disruptive behavior and impulsivity

Regarding PAH, Dr. Frederica Perera, Director of Columbia Center for Children’s Environmental Health, commented, “All of these sources are very common in urban areas and we were concerned about learning more about what those effects might be.”

Perera added, “Children of mothers who were exposed to high levels of PAH during pregnancy had five times the odds of having an increased number and degree of behavioral problems.”

Here is a small documentary on ADHD:

The study was focused around the Washington Heights area of Manhattan, where pollution is known to be rampant. African American and Dominican mothers and their children were primarily assessed.

The Columbia research team remarked that more research is needed to fully understand how pollutants affect the onset of ADHD. “This is the first study that has looked at this particular class of pollutants,” Perera commented.

Likewise, ADHD itself can be difficult to diagnose, as it is hard to define where normal levels of inattention, hyperactivity, and impulsivity end, and where significant levels requiring treatment begin.