Using those hot-air hand dryers in restrooms actually spread bacteria, including fecal bacteria on your hands, according to a new study conducted at UConn.
“In most institutions, toilets don’t have lids and when you flush them you get a little bit of an aerosol,” said Dr. Peter Setlow, a molecular biology and biophysics professor at UConn Health.
So, where does that toilet plume go?
“The hand dryers grab that air in the bathroom and accelerate it,” Setlow said.
During the study, plates were placed under hand dryers to collect the bacteria being blown out of the hand dryer.
“We’d get up to 150, 200 individual bacterial colonies and obviously different because they were different colors, different shapes, different smell,” Setlow said.
They tested 36 bathrooms multiple times and got similar results. The study was done in a research area in the academic building at UConn Health in Farmington not open to the public. However, Setlow said hand dryers in most public bathrooms work the same way.
“The bacteria that are blown from the hand dryers are coming from the bathroom air,” said Setlow.
Setlow has been studying molecular biology for 50 years. He said of the nearly 500 papers he’s helped author, this one, published in Applied and Environmental Microbiology, has gotten the most attention.
People who spoke with NBC Connecticut said news of the study may make them change their habits.
“It definitely makes me hesitate to use them,” Amy Anderson, of West Hartford, said.
"I’d just shake off your hands maybe. Just dry them on your sweatshirt,” said Sean Brierty, of Barkhamsted.
Setlow said adding HEPA filters to the hand dryers reduced the amount of bacteria four-fold when they were attached to the same dryers previously tested.