When babies crawl their movement across floors especially carpeted surfaces kicks up high levels of dirt skin cells bacteria pollen and fungal spores a new study has found. The infants inhale a dose of bio bits in their lungs that is four times (per kilogram of body mass) what an adult would breathe walking across the same floor. As alarming as that sounds lead researcher Brandon Boor of Purdue University is quick to add that this isn’t necessarily a bad thing. We are interested in the biological material an infant inhales especially during their first year of life when they