ADHD News & Research

Air Pollution Linked to ADHD

New research suggests that a pregnant mother’s exposure to air pollution may increase her baby’s odds of developing attention deficit disorder.

November 13, 2014

Mothers-to-be know they need to be vigilant about what they eat and drink, because of the impact it can have on their developing fetus. Previous reports have even shown that the expectant mother’s habits and experiences – including stress, sleep and mood – can affect the baby’s future health. Now, a new study from the Mailman School of Public Health at Columbia University shows that even air quality can influence cognitive development en utero.

The team had previously found a correlation between polycyclic aromatic hydrocarbons (PAHs) – the pollutants emitted in the air from burning fossil fuels like car exhaust or heating – and developmental delays, reduced IQ, and attention problems in children age 3-6. In their most recent research1, they focused specifically on how PAHs might be connected to concentration, and contribute to ADHD symptoms in children.

To evaluate PAH exposure, scientists measured their levels in cord blood and the mother’s blood after giving birth. Additionally, they tested urine samples from the children between ages three and five. They found that when mothers had higher levels of PAH during pregnancy, children were five times more likely to show symptoms of ADHD than were children whose mothers had lower PAH levels. Frederica Perera, director of the center for environmental health sciences at the Mailman School, is hopeful that if further research establishes that PAHs contribute to ADHD, it could be a new path for finding new treatments and preventative measures for ADHD.

Dr. Sandy Newmark, founder of the Center for Pediatric Integrative Medicine in San Francisco, gave his expert opinion: “This study should not come as a surprise. Although there is a strong genetic component to ADHD, there is an equally strong environmental influence, and this influence begins with the prenatal environment. Previous studies have connected pesticide exposure during pregnancy to an increased incidence of ADHD, and a very recent study correlated prenatal antidepressant use with an almost twofold increase in ADHD incidence. Other research has shown that ADHD incidence increases with exposure to pesticides and other environmental pollutants during childhood. The bottom line is that the developing brains of our children are highly susceptible to environmental influences of many kinds, and we need to continue to research these exposures and prevent damage whenever possible.”

PAHs stay in the body for a long time, and some people may be more susceptible to them breaking down and becoming toxic while others experience a more limited effect from exposure. While pregnant women cannot go back and erase previous exposure, they can do their best to avoid fossil fuel heating sources and heavy traffic areas during pregnancy, ensure that cooking areas are well-ventilated, and avoid inhaling smoke from burning candles, incense and especially cigarettes. Expectant mothers can also try to offset the effects of PAHs by consuming antioxidant-rich fruits and vegetables that will work against the damage. On a public scale, communities can work with legislators to enact clean air laws that would improve air quality. While limiting PAHs is one step towards slowing ADHD diagnoses, researchers stress that identifying as many potential genetic and environmental factors as possible is crucial to reducing their effect on mothers and their growing babies.

1 Perera, Frederica P., et al. “Early-Life Exposure to Polycyclic Aromatic Hydrocarbons and ADHD Behavior Problems.” PLoS ONE, vol. 9, no. 11, May 2014, doi:10.1371/journal.pone.0111670.