Many of us don't give much thought to the air we breathe. But if you live in a city, near a major road, next to an industrial plant or even just have a wood burning stove, that air is often laced with miniscule pollutants. After we inhale, those particles can lodge in our lungs and travel throughout the body. For pregnant women, this may put their unborn children at risk.

A new study, published today in the journal Nature Communications, found that particles of the air pollutant black carbon can get inside the placenta, the organ that develops during pregnancy to provide the developing baby with oxygen and nutrients. The study also found that higher pollution exposure for mom was correlated with more black carbon in the placenta tissue.

The findings could potentially illustrate how air pollution impacts the health of young children before they've taken their first breaths.