Infants inhale a lot of dust when they crawl across the living room floor—roughly four times more dirt, skin cells, bacteria, pollen, and fungal spores than adults per kilogram of body mass, according to a new study in Environmental Science & Technology. This finding is disturbing enough, but how researchers figured this out without shoving babies’ faces into carpets is the real kicker. The team used robotic, crawling baby, fashioned from tinfoil and nightmares.
Human babies are uniquely bad at walking — we’re the only mammals who have to crawl for months before figuring out adult gaits. Some anthropologists even suspect that babies didn’t need to crawl once upon a time and that we only started once our parents started living in homes with wooden floors. Crawling, then, is a neat evolutionary trick. That is, until you consider the fact that it puts our faces right in the germs and particulate matter that live on our floors.
Worse, babies are basically bacteria-loving vacuum cleaners. Adults filter dust by breathing through through their noses, but small children “breathe through their mouths, and a significant fraction is deposited in the lower airways,” coauthor on the study Brandon Boor of Purdue University said in a statement. “The particles make it to the deepest regions of their lungs.” Boor’s robotic baby from hell demonstrated this and helped scientists measure just how much gunk the average child gets in his or her lungs while scurrying around on a dirty floor.
But it’s not all bad news. Boor says “numerous studies have shown that when an infant is exposed to a very high diversity of microbes, at a high concentration, they can have a lower rate of asthma later in life. Such exposures act to stimulate and challenge your immune system.” In other words, infants crawl around and inhale everything on your living room carpet—and that may be a good thing. Scientists are increasingly encouraging parents not to sterilize everything toy, and ascribing to the microbiome-driven notion that a little dirt might even be a good thing.
“While our research established new methods for infant microbial exposure assessment, much remains to be discovered,” Boor says. “I hope to continue to work with microbiologists and immunologists to better understand the role of indoor air microbes and allergens on early-childhood health.