Those Bathroom Hot Air Dryers? They Blow Bacteria Back At You

Mar 7, 2018

Are bathroom hot air hand dryers a better choice than paper towels?

They can be less expensive and can help to save trees, but a new paper published by University of Connecticut researchers finds they also circulate bacteria. And that bacteria may end up coating your hands right after you’ve washed them.

Microbiologist Peter Setlow is a lead researcher on the study. In his lab at UConn Health, he works with large amounts of non-pathogenic spores, which he discovered had made their way into bathrooms around the building. Here are highlights from a recent conversation he had with Connecticut Public Radio’s Diane Orson.

Connecticut Public Radio sought comment from experts in the air dryer industry, but as yet have not received a response.

On the study...

"We would go into men’s and women’s bathrooms in various places at UConn Health in the basic science research area. We would take agar plates that are used for growing bacteria and put them under the hand dryers --when the hand dryers were on obviously -- and hold them there for one minute or so. Then, we’d put them in an incubator so they could grow overnight."

On what they found...

"We found lots of bacteria. And we found bacteria that were identical as far as we could tell to the bacteria that would come from the spores that we’d been preparing in my laboratory. And we found many other different kinds of bacteria, many of them common skin flora."

On what should be done...

"All I can say is what I’ve done. I don’t dry my hands on hand dryers anymore, especially if I go into bathrooms in airports or bus stations. I will say that after this paper where we’d surveyed 36 bathrooms in UConn Health in the basic science research areas, paper towel dispensers were put in all of those bathrooms."

Is your concern hygienic or safety, or both?

"A little of both. The safety issue is very, very small. But it is there. I’d like to keep the bacteria that aren’t mine from getting on me. Simple as that."

On paper towels versus hot air hand dryers...

"This is not a simple field to decide what should we do.

"I would presume that paper towels with the attendant environmental costs, cost more probably. Hot air hand dryers are convenient and a little more worry-free. But you have to balance that against the fact that they almost certainly do spray bacterium.

"I think it’s one of these things that you want people to know so they can make an informed decision. It’s complicated."

NOTE: UConn Health is an underwriter on Connecticut Public Radio.