Add behavioral problems to the list of health and developmental impacts linked to air pollution exposure.
According to a study published this week in PLOS ONE, pregnant mother’s exposure to air pollution can increase her unborn child’s chance of being diagnosed with attention deficit hyperactivity disorder (ADHD). The study, which looked at 233 pregnant mothers in New York City, found that the children of women who were exposed to high levels of polycyclic aromatic hydrocarbons (PAHs) during pregnancy were five times more likely to have symptoms that are in line with ADHD.
“This study suggests that exposure to PAH encountered in New York City air may play a role in childhood ADHD,” the study’s lead author Frederica Perera, professor of Environmental Health Sciences at Columbia’s Mailman School of Public Health, said in a statement. “The findings are concerning because attention problems are known to impact school performance, social relationships, and occupational performance.”
PAHs are toxic pollutants that are released through the burning of coal, oil, gas or tobacco, and are also formed by cooking meat over high temperatures. All of the mothers followed by the researchers breathed in some PAHs during their day-to-day lives, but the study notes that exposure to PAHs is often more acute in non-white populations.
“Urban, minority populations in the U.S. often have disproportionate exposure to air pollution and are at greater risk for adverse health and developmental outcomes from this exposure,” the researchers wrote.
That link between socioeconomic status and air pollution exposure has been pointed out in other studies: earlier this year, researchers from the University of Minnesota found that minorities, as a whole, breathe in more pollution than whites, findings that one of the researchers told the Washington Post “likely have health implications.”
The Columbia researchers aren’t sure yet exactly how PAHs affect the developing brain and lead to higher risk of ADHD. The pollutants might act as endocrine disruptors, they write, or might lead to decreased oxygen and nutrient exchange in the developing brain. But the study makes it clear that PAH exposure during pregnancy should be avoided as much as possible — both before and after a child is born.
“The prenatal period is critical because of the extensive structural and cellular-level changes that occur during this stage of development,” the authors explained. “However, because brain development and growth occurs throughout childhood, postnatal exposures to environmental pollutants may also affect children’s neurodevelopment and behavior.”
Previous research has linked air pollution exposure to other developmental delays and health problems. One study, also by researchers from Columbia University, linked high prenatal exposure to air pollution (including PAHs, tobacco smoke and pesticides) to cognitive developmental delays in the first three years of a child’s life.
Studies have also found that PAH exposure can affect a child’s IQ and behavior. Another study from 2013 found that high exposure to air pollution in the first two months of pregnancy greatly increases an unborn child’s chances of birth defects.
Air pollution has also been tied to serious health impacts in adults. Long-term exposure has been linked to kidney damage, stroke, heart attack, irregular heart rhythms and death. These severe health affects are part of the reason why some health care professionals have lauded the Environmental Protection Agency’s plan on carbon emissions from power plants, which the agency proposed this summer.
“The resulting improvements in air quality associated with a strong carbon pollution standard would have nearly immediate benefits by reducing illness and premature deaths,” Harvard researchers write in a study on the benefits of carbon regulations. “Moreover, decreased air pollution will help to continue reversing the damage brought by years of acid, nitrogen deposition, and mercury deposition. In so doing, carbon pollution standards can protect public health and help restore forests, waters, and wildlife, while also mitigating climate change.”