Ordinary dust in your home can tell a lot about you — including the region where you live, what pets you have and even the gender of the people who live with you.
The bacteria and microbes in household dust can inform scientists about what goes on in homes and about the people who live there, they report after analyzing dust samples from 1,200 U.S. homes.
Indoor and outdoor dust was collected as part of a citizen science effort known as Wild Life of Our Homes, and was studied by the researchers from North Carolina State University and the University of Colorado, Boulder.
"Every day, we're surrounded by a vast array of organisms in our homes, most of which we can't see," said study co-author Noah Fierer of the Colorado school's Department of Ecology and Evolutionary Biology. "We live in a microbial zoo, and this study was an attempt to catalog that diversity."
The average home in the study was home to around 2,000 species of fungi and some 5,000 bacterial species, the researchers report in the journal Proceedings of the Royal Society B.
Fungi are the best clue to the home's geographical location, while bacteria can tell a lot about its inhabitants.
"Geography is the best predictor of fungi in your home," said Fierer, explaining that the majority of fungi come from external sources, blown into a home from leaves and soil from outside or carried in on clothing.
Bacteria, on the other hand – generated within the home – allowed the researchers to draw conclusions about the presence of pets like dogs or cats, and even the gender ratio of the home's occupants.
Homes that have all male occupants, they said, will show a separate bacterial makeup from a residence housing both males and females.
"There are some kinds of bacteria that are more common on women's bodies than on men's, and we can see the impact of that on the bacteria found in house dust," said Fierer.
People shouldn't be concerned about the microbes in their homes, he continued; even though they're all around us there and even on our skin, most are completely harmless and some may even be beneficial.
Additionally, there's not much we can do about it, according to study lead author Albert Barbaran, a graduate researcher in Fierer's department.
"One of the key takeaways is that if you want to change what you breathe inside your house, you would either have to move very far away or change the people and the pets you live with," he said.
