In an infant's initial four months of life, exposure to pollutants like nitrogen dioxide can cause negative effects on motor and mental development, but according to a new study, breast-fed babies are better protected from these airborne toxins.

Researcher Aitana Lertxundi, along with her team, monitored rural, pregnant women in 2006 and analyzed samples from 638 women and their infants at 15 months.

Researchers found an inverse relationship between exposure to pollution particle matter and babies' motor development, according to Science Daily.

Lertxundi also studied the effects of NO2 on mental development.

In breastfed babies, neither the PM2.5 particle matter nor the NO2 were shown to have a harmful effect on babies for at least four months, suggesting that breastfeeding has a protective effect.