New research published this week links early-life traffic-related air pollution exposure to the development of hyperactivity in children. Biological mechanisms, including narrowed blood vessels and toxicity in the brain’s frontal cortex, are triggered by air pollution, according to the study’s author, Dr. Nicholas Newman. The study was conducted by the research teams at the University of Cincinnati and the Cincinnati Children’s Hospital Medical Center. The results were published May 21 in Environmental Health Perspectives, a peer-reviewed journal published by the National Institutes of Health (NIH).

Hyperactivity symptoms

Hyperactivity is one of three major groups of symptoms associated with attention deficit hyperactivity disorder, or ADHD. The disorder affects 6-7% of all children. Symptoms typically appear by age 7. Symptoms of hyperactivity include restlessness, impulsiveness, and a lack of focus that can affect academic performance. More specifically, according to the NIH, there are five common symptoms of hyperactivity in children:

• Fidgets with hands or feet or squirms in seat
• Leaves seat when remaining seated is expected
• Runs about or climbs in inappropriate situations
• Has difficulty playing quietly
• Is often “on the go,” acts as if “driven by a motor,” talks excessively

Medication therapy is recommended only for those with the most severe symptoms. As many as half of the children with ADHD continue to have symptoms into adulthood.

Researchers followed more than 500 cases

Researchers followed the health of more than 500 children living in the Cincinnati metropolitan area who were born between 2001 and 2003. They observed a significant increase in hyperactivity among those children exposed to elevated levels of elemental carbon pollution from vehicular traffic. Cincinnati was recently rated #10 among the worst cities in the United States for year-round particle pollution. The ratings were published in the American Lung Association’s State of the Air 2013 report.

The new research on the link between particle air pollution and hyperactivity seems to confirm the findings of a group of researchers in 2011 in Canada, who found a strong association between particulate pollution and the prevalence of ADHD. That study, titled, “Attention-deficit hyperactivity disorder in children chronically exposed to high level of vehicular pollution,” was published by the NIH in a Canadian journal.

Other pollutants also linked to ADHD

Other environmental pollutants have also been linked to ADHD, includingorganophosphatepesticides that are used by growers of peaches, apples, grapes, green beans, pears and other fruits and vegetables. Exposure can occur through contacting pesticide-contaminated surfaces and also through breathing air near pesticide applications, according to experts. Studies have noted the strongest links in children in agricultural communities, but one study published in the June 2009 issue of Pediatrics found a link even in the general population.