Can Jet Hand Dryers Really Blast Out a Germ Cloud? Well, Yes and No


A recent study analyzed the germ-spreading capability of jet air hand dryers like this Dyson Airblade. Marcin Wichary/Flickr
A recent study analyzed the germ-spreading capability of jet air hand dryers like this Dyson Airblade. Marcin Wichary/Flickr

The last thing people want in a public restroom is more germs, but depending on how they dry their hands, that may be exactly what they are spreading.

The latest in a vein of research studying the effects of hand washing, hand dryers and germs shows that, in some cases, old-fashioned might be better. A recent study published in the Journal of Applied Microbiology compared different hand drying methods and their effect on germ dispersal.

Just a Slight Breeze

Researchers discovered that those deafening jet air dryers — touted by manufacturers for their cleanliness — can actually spread viruses across a distance of nearly 10 feet (3 meters). The jet air dryers are activated when a person vertically inserts their hands inside the machine, causing powerful air jets to turn on. However, researchers found that these air jets spread viral plaques, which are groups of clumped viruses, at a rate 1,300 times more than paper towels. The study did not investigate the distribution of bacteria, which are bigger than viruses. 

The findings were recorded after participants dipped gloved hands into a solution that included an innocuous virus. Participants then shook excess liquid off their gloves and used one of three drying method: paper towels, warm air dryers and jet dryers. Researchers then collected air samples at a variety of distances from each type of dryer. They also used petri dishes to collect viruses that landed on surfaces adjacent to the drying stations. In the end, the jet air dryer spread viruses the furthest.

The implications are significant, not only for people who cringe at the idea of making a public restroom "germier," but for hospitals whose business is making people well.

Not so fast, says Dyson, the company makes the popular Airblade jet air dryers. In 2008, the Dyson jet air dryer was the first such product to earn accreditation from the Royal Society for Public Health. Dyson argues that 2015 research found that up to 88 percent of unused paper towels tested in the U.S. contain bacteria, which can transfer to hands.

Dyson also contends that the recent Journal of Applied Microbiology study artificially inflated germ concentrations. In a real-life situation, the company says, most people would not have the sheer number of viruses on their hands as was used in the study, nor would they stick their unwashed, virus-coated hands in a jet dryer without rinsing and cleaning first. 

There Is Another Path

What's the best course of action for hand washers? Even the professionals are debating the issue. An April 2016 study published in Infection Control & Hospital Epidemiology compared the three-step handwashing method outlined by the U.S. Centers for Disease Control to the six-step strategy of the World Health Organization. The study, which observed doctors and nurses using both of these handwashing techniques, found the six-step method got rid of more bacteria. This method includes using an alcohol-based hand rub.

The issue of compliance when implementing the six-step process came up during the study. "Only 65 percent of providers completed the entire hand hygiene process, despite participants having instructions on the technique in front of them and having their technique observed," says Jacqui Reilly, the study's lead author. "This warrants further investigation."

For those who still need to dry their hands as the debate rages on, the best bet may be a time-tested paper towel dispenser followed by liberal application of hand sanitizer. Oh, and don't forget to scrub with soap in the first place.