“All Dyson Airblade hand dryers have HEPA filters that capture particles as small as bacteria from the washroom air before it leaves the machine,” the company said. “Dyson Airblade hand dryers are proven hygienic by university research and are trusted by hospitals, food manufacturers and businesses worldwide.”
Whether hand dryers do, in fact, spread pathogens is a matter of dispute among scientists.
“The hot air will kill the bacteria on the hands, but some studies have found they will also deposit bacteria in the restroom on your hands — i.e., from the air,” said Charles P. Gerba, a microbiologist at the University of Arizona.
A study published in 2016 in The Journal of Applied Microbiology found that jet air dryers — high-powered machines like the one Ms. Ward used — contaminated the surrounding area with 1,300 times as many viral particles as a paper towel would. Standard hand dryers — those that simply blow warm air — spread far fewer particles, but still 60 times as many as a paper towel. (Dyson said when that study was released that it had been conducted under unrealistic conditions: Participants’ hands were thoroughly coated with a virus, which would not be the case for a typical pair of just-washed hands.)
A similar study in 2014, using a bacterium instead of a virus, found that jet air dryers spread 4.5 times as much bacteria as warm air dryers, and 27 times as much as paper towels — but the study was funded by a trade association for paper manufacturers. Another study published in 2010 found that jet air dryers resulted in fewer bacteria on the hands than warm air dryers — but it was funded by Dyson.
One of the few independently funded studies on the subject, published by the Mayo Clinic in 2000, found no statistically significant hygienic difference between dryers and paper towels.