Washing your hands thoroughly to get rid of as much bacteria as you can is important, but the way you dry them could be rapidly spreading germs. To find out what the best method is for drying, a team of researchers from the University of Westminister compared people who dry their hands with paper towels to those who rely on air dryers or jet dryers to do the job.

For the study, published in the Journal of Applied Microbiology, researchers asked participants to dip their hands into a solution swimming with a harmless virus called MS2. Petri dishes were placed around the area to collect any traces of the virus as participants dried their hands. Researchers also collected samples from the air as participants used each one of the three drying methods.

The researchers found significantly different rates among the spread of germs. The study’s authors wrote: "These differences in results between the three hand-drying devices can be largely explained by their mode of drying the hands.”

Participants who used the Airblade jet dryer manufactured by Dyson spread 60 times more germs than standard air dryers and 1,300 times more germs than those who used paper towels. The germs were spread nearly 10 feet away from the dryer itself, making anyone surrounding the dryer at risk for being exposed to germs.

In 2014, another team of researchers from the University of Leeds conducted a similar study that found airborne germs traveled nearly 27 times more compared to germs found on the surface of paper towel dispensers. What’s worse is 48 percent of the bacteria dried off the participant’s hands still remained in the atmosphere 15 minutes after they were done drying their hands with the jet air hand dryer.

"Next time you dry your hands in a public toilet using an electric hand dryer, you may be spreading bacteria without knowing it,” said Mark Wilcox, the lead author of the 2014 study. “You may also be splattered with bugs from other people's hands."

Previously, makers of jet driers, such as Dyson, have pointed out problems in another study’s findings, highlighting how unrealistic the results were because hand washers wouldn’t have such a high level concentration of germs on their hands. Because the research wasn’t carried out in a real-world scenario, Dyson claims scientists are manipulating the study in order to scaremonger consumers into using paper towels.

In 2014, Kimberly-Clark, the manufacturer of air driers, teamed up with the European Tissue Symposium (a tissue paper trade association), to produce a body of research that found jet dryers create “significant hygiene risks.” In addition, the study concluded that paper towels reduced bacteria by up to 77 percent while jet driers increase bacteria on the hands by 42 percent.

“[The researcher’s] methodologies are biased and misleading,” said a Dyson spokesman. “Among the false and unsubstantiated claims are that 'jet hand dryers' increase bacteria on people's hands. The Dyson Airblade hand dryer uses a HEPA [high efficiency particulate air] filter to remove 99.9% of bacteria present in the air used to dry hands. Testing confirmed this, but still reported an increase — a contradiction that is not explained."

Source: Kimmitt PT and Redway KF. Evaluation of the potential for virus dispersal during hand drying: a comparison of three methods. The Journal of Applied Microbiology . 2016.