Childhood smog exposure linked to poor reading, math abilities

NEW YORK — Studies continue to show that exposure to air pollution and smog can be detrimental to our physical health. Now, researchers from Columbia University find childhood smog exposure can also harm cognitive health and learning ability. Their study reveals children encountering elevated air pollution levels are more likely to exhibit more impulsive behavior later in childhood.

Moreover, increased childhood smog exposure shows a link to poor academic skills (spelling, reading comprehension, math) in early adolescence. In many cases, behavioral control issues during childhood act as a pre-cursor to academic troubles a few years later.

“Children with poor inhibitory control are less able to override a common response in favor of a more unusual one–such as the natural response to say ‘up’ when an arrow is facing up or ‘go’ when a light is green–and instead say ‘down’ or ‘stop,'” says first study author Amy Margolis, PhD, associate professor of medical psychology in the Department of Psychiatry at Columbia University Irving Medical Center, in a university release. “By compromising childhood inhibitory control, prenatal exposure to air pollution may alter the foundation upon which later academic skills are built.”

“When evaluating student’s learning problems and formulating treatment plans, parents and teachers should consider that academic problems related to environmental exposures may require intervention focused on inhibitory control problems, rather than on content-related skill deficits, as is typical in interventions designed to address learning disabilities,” Prof. Margolis adds.

Air pollution before birth is just as influential

Researchers note it’s always a good idea to shield today’s youth from smog as much as possible. However, these findings actually indicate that even prenatal air pollution exposure can extract a cognitive toll.

“This study adds to a growing body of literature showing the deleterious health effects of prenatal exposure to air pollution on child health outcomes, including academic achievement,” explains study co-author Julie Herbstman, PhD, CCCEH director and associate professor of environmental health sciences at Columbia Mailman School. “Reducing levels of air pollution may prevent these adverse outcomes and lead to improvements in children’s academic achievement.”

Moreover, this work gels nicely with prior research conducted at Columbia that found a DNA marker for prenatal airborne polycyclic aromatic hydrocarbons (PAH, a major part of air pollution) with a connection to both ADHD symptoms and irregular self-regulatory capacity development.

Study authors assessed a total of 200 children living in either Manhattan or the Bronx, New York during this study. All of those kids were already being studied as part of a longitudinal cohort study set up by Columbia. Prior to each child’s birth, the team collected measures of PAH from their mothers during the third trimester of pregnancy. The time is important because babies are especially vulnerable to environmental factors during the third trimester of a pregnancy.

Researchers then assessed each child’s inhibitory control around the age of 10. Similarly, each child participated in academic tests around the age of 13.

So how exactly does inhibitory control play into learning abilities?

Researchers explain that when a student learns something new, they usually have to override a previous habit in order to successfully incorporate this new lesson into their skillset.

For instance, while learning vowels, children discover that the letter “a” has a short vowel sound like “a as in apple,” except when a “magic E” follows a consonant (like in the word “rate”). In such cases, the vowel needs a longer sound.

The team published their findings in the journal Environmental Research.