We tend to think of a house as a shield against the outside world. When inside, we feel protected from bad weather, bad people, and perhaps even bad germs. But far from being a barrier against microbes, our homes (and buildings in general) are populated by a universe of tiny roommates that interact with our bodies and our microbiomes in myriad, complex ways.
“From birth, microbes inside buildings seed, colonize, and transiently occupy our bodies,” writes Jordan Peccia in an essay published today in the journal Trends in Microbiology. Peccia, a professor of chemical and environmental engineering at Yale, argues that as our understanding of microbes deepens, so too should our understanding of the ways our built environment influences those microbes and, as a consequence, our health.
“One big question becomes how building design (e.g., the geographical layout, the building materials, occupancy, and ventilation) modulates microbial exposure, and our own microbiomes,” Peccia said in a statement.
We spend ninety percent of our lives indoors, where we interact with microbes from people, pets, and other sources. Other microbes come from the building structure itself. For example, when a building has water damage it can lead to fungal and bacterial growth. Some of these microbes can make us sick, which has led to technological advances in disinfectant surfaces, air ventilation, and anti-microbial building design. But Peccia warns that a more nuanced understanding of the relationship between these bugs and our health is warranted.
“It’s a common misconception that all microbes found in one’s home are hazardous to your health,” Peccia said. “Many have no impact on health, while some may even be beneficial.”
One source of good bugs might be our pets. Peccia and his co-author, Ph.D. student Sarah Kwan, point to studies showing that children who grow up on Bavarian or Amish farms, in close proximity to livestock, have lower rates of asthma than urban kids. The suggestion is that the farm kids’ exposure to animal microbes boosts their immune defenses. Citing studies demonstrating that effect in lab rats, the authors ask: “Can dog ownership be an urban equivalent of growing up on an animal farm?”
Should we all run out and bring home puppies? Not necessarily, Peccia said. We need more than a “one-size-fits-all” approach. The authors advocate a increased focus on studying how buildings mediate our exposure to microbes. From there, we can design buildings that protect us from those bad bugs, and facilitate our exposure to the good ones.