Smog Makes It Hard to Breathe, and It Might Be Lowering Kids' IQ Too

Researchers at Columbia University say the impact of air pollution can be seen especially in children born into low-income families.

(Photo: Dan Kitwood/Getty Images)

May 27, 2015· 2 MIN READ
Culture and education editor Liz Dwyer has written about race, parenting, and social justice for several national publications. She was previously education editor at Good.

It obscures landmarks such as the Eiffel Tower, stings our eyes, and chokes our lungs. Now a groundbreaking study led by researchers at Columbia University has found another toxic effect of air pollution: It might be lowering our IQ. According to the researchers, the impact seems to be worst on kids from low-income families.

The study, which was published in the medical journal Neurotoxicology and Teratology, is a chilling confirmation of the dangerous connection between poverty and air pollution.

The researchers followed 276 pairs of New York City moms and children from the time the women were pregnant until the kids were seven. According to the study, pregnant moms who were struggling to make ends meet and who were exposed to high levels of airborne polycyclic aromatic hydrocarbons—a dangerous compound that can be found in car exhaust, factory emissions, and burning garbage—had children who displayed negative health symptoms. The seven-year-olds from disadvantaged economic backgrounds "significantly scored lower on tests of full scale IQ, perceptual reasoning, and working memory."

Economically disadvantaged kids may also be affected by “a poor prenatal diet and exposure to other chemical toxicants, such as lead, secondhand smoke, and other air pollutants,” Frederica Perera, professor of environmental health sciences at Columbia University's Mailman School of Public Health and senior author of the study, wrote in an email. However, other studies have shown that low-income, nonwhite people are more likely to live in neighborhoods with higher levels of pollution: They’re housed closer to factories and highways, and there is usually less green space. According to a UNICEF report released last fall, nearly one in three American kids is growing up in a household with an income below $31,000. That's millions of kids who could have a lower IQ as well as reduced memory and reasoning skills. Essentially, the capability of America’s future workforce could be hamstrung by smog.

The latest findings back the results of a study by the Columbia researchers that found that low-income kids who are exposed to significant air pollution are more likely to have developmental delays by age three. Those children are also more likely to have “reduced verbal and full scale IQ at age five, and symptoms of anxiety and depression at age 7."

So, Why Should You Care? The impact of air pollution on in utero babies is potentially much bigger than a few hundred moms and kids living in New York City. Even if you are well-off enough to live in a penthouse on the edge of Central Park, your risk—or that of your children—probably isn't zero.

“Mechanisms underlying interactions between toxic pollutants and psychosocial factors such as poverty are not well understood,” wrote Perera in her email. “It is possible that PAH are equally toxic under conditions of low and high economic hardship, but that low hardship families have unmeasured resources positively affecting the health and development of children and buffering the adverse impact of PAH exposure.”

It may be difficult for individuals from socioeconomic disadvantaged families to limit their exposure to sources of PAH, such as vehicle exhaust. But Perera suggests “they can try to do so by avoiding heavily trafficked areas as much as possible and not leaving the window open during heavy pollution days.”