There aren't any calories in air. But there are pollutants including chemicals called Polycyclic Aromatic Hydrocarbons, or PAH. If that sounds like a mouthful to you, you're right.

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Researchers at Columbia's Mailman School of Public Health found pregnant moms exposed to the highest concentrations of PAH were more than twice as likely to have obese children by age seven compared to those with lower levels of exposure. PAH is part of the by-product from pollutants like diesel fuel exhaust, cigarette smoke, and oil furnace fumes.

Andrew Rundle, Assoc. Professor of Epidemiology, Columbia Mailman School of Public Health said, “Anywhere we are burning something you get the production of PAHs and they are known carcinogens but they are also known to have other affects on the body including it appears they have an effect on the endocrine system. There's different data sets that suggest things that happen in-utero or during the pre-natal period can echo across the child's development into adulthood and put them at risk for higher weight or obesity.”

Researchers tracked more than 700 moms-to-be living in Washington Heights and the South Bronx. Where they've dubbed pollutants in high traffic areas as "obesogens".

Over the course of two days during their third trimester. The women wore backpacks like this with air pumps attached to measure all the pollutants in the air.

Rundle said, “Obesity is an epidemic of one thousand paper cuts. It's just all of these things pushing us in sort of the wrong direction when it comes to calorie intake.
There's things pushing us in the wrong direction when it comes to being physically active. On top of that there are other things going on and pollution may be part of that.”

New York has already been working to drive pollution rates down by doing things like converting diesel buses and apartment building furnaces to cleaner fuel sources. Just like encouraging a greener diet to trim waistlines, researchers said their findings support more work to be done on a greener environment too.