Hand dryers, even the fancy ones, suck: new study

Paper towels are rare in Australian restrooms, and it’s the same in Japan.

But new research confirms what we’ve been saying for a decade: hand dryers spew bacteria into the air and onto people.

hand-dryerConventional (warm air) and high-velocity (jet air) dryers alike spread bacteria into the air, according to the study. Airborne germ counts near warm-air dryers were found to be 4.5 times higher than the counts near paper towel dispensers, and the counts near jet air dryers were a whopping 27 times higher.

It doesn’t take a lot to figure out what’s probably going on here. As study leader Prof. Mark Wilcox, professor of medical microbiology at the University of Leeds, told The Huffington Post in an email:

“While jet air dryers are good at hand drying, they achieve this by using air velocities of about 400 miles an hour … Unfortunately, this means that the dispersed water droplets (containing more or less bacteria/viruses depending on how hands were washed and how contaminated they were in the first place) will be fired longer distances and some will remain suspended in the air for many minutes (possibly hours).”

For the study, the researchers contaminated people’s hands with harmless Lactobacillis bacteria that normally aren’t found in bathrooms. Then they measured levels of the bacteria in the air at distances of up to two meters away from the dryer after the people had dried their hands.

“This research was commissioned by the paper towel industry and it’s flawed,” a spokesperson for dryer maker Dyson told The Telegraph.

Wilcox acknowledged that the study was funded by the European Tissue Symposium, an association of tissue paper producers. But the group “played no part in the results analysis,” he said, adding that he had no ties to ETS other than the financial support for the study.

The study was published in the Journal of Hospital Infection and presented at a recent meeting of the Healthcare Infection Society in Lyon, France.

 

  • Stephen Brand

    If the handwashing had been done correctly, then there should have been no bacteria in the residual water left on the hands anyway

    • Randy Lyons

      Incorrect. The assumption is that there will always be some microbial load present. How do we know if the water is free from contamination? It should be, but do we really know? The purpose of fully drying the hands afterwards is to remove the moisture from the hands to limit and/or reduce replication of any microbes left behind. Excess moisture is also the idea vehicle to transfer microbes from one surface to another.

  • James S.

    Germs are in the air – even after proper washing using paper towels or hand dryers the microbes will be on your hands before you exit the bathroom door.