Science suggests that high-tech hand dryers may actually be “microbial catapults” that fire bacteria back onto your skin.
Since we were children, we are taught to wash our hands responsibly, confident that soap and water will leave our hands spotless.
However, according to a series of increasingly disturbing studies, the last ten seconds of your time in the bathroom (the drying phase) could be throw your efforts to the ground — or even worse.
In fact, hand dryers can cause more problems than they solve.
In 2010, one led by Anna Snellingfrom the University of Bradford, and published in Journal of Applied Microbiologybegan by exposing for the first time a counterintuitive truth about human skin.
Snelling’s team followed 14 volunteers as they tested three different types of air dryers. He asked them to wash their hands and then dry for 15 seconds with a hairdryerthe first time rubbing their hands together, and the other time keeping them still.
Rubbing your hands made things significantly worse. When the volunteers held their hands still and dried under the hot air coming from the dryer, the bacterial count decreased by 37%.
However, as soon as they started to rub your hands togethersomething many people do to speed up the process, bacterial count soared by 18%. “When we rub our hands, we bring a lot of bacteria to the surface from the pores of our skin,” explained Snelling, cited by .
But the fact that the bacterial count, without rubbing your handshave decreased after exposure to hot air, doesn’t mean that air dryers in public bathrooms necessarily be our allies.
While Snelling focused on what lives on the skin, in more recent studies, other researchers analyzed what lives in the air around us.
A study from the University of Westminster compared “biological footprint” of three ways to dry your hands: paper towelstraditional hot air dryers and high speed jet air dryers.
The study authors found that jet air dryers can increase bacterial counts on fingertips by up to 42%, while traditional hot air dryers increased bacterial counts by impressive 194%.
But there are even worse news.
The truly frightening data comes from a 2015 publication in Journal of Hospital Infectionin which researchers PT Kimmittt e K. Redwayfrom the University of Westminster, discovered that jet dryers work like real microbial catapults.
These machines can disperse 190 times more viral particles than paper towels, projecting them up to 3 meters away. Basically, the jcto dryer is less of a cleaning tool and more of a cleaning tool. a viral hurricanewhich transforms pathogens into a fine mist that remains in the air.
These results were corroborated by several other studies (, ), in which researchers concluded that jet air dryers shouldn’t of everything being used in hospital environments.
Then, what should we do? The best answer is probably the simplest.
In 2012, a Mayo Clinic meta-analysis on Mayo Clinic Proceedingsanalyzed 12 different studies to settle the debate. The conclusion was definitive: “From a hygiene point of view, paper towels are superior and should be recommended where hygiene is paramount, such as hospitals and clinics.”
The secret lies in the mechanical action. Unlike air dryers, which rely on evaporation and heat, paper towels use friction; they literally “clean” the bacteria and viruses that survived the initial wash.
In Snelling’s study, paper towels managed reduce by half bacterial count even when the user scrubbed vigorously. Not limited to drying: actively complete cleaning work.
Rarely does science ask us to return to simpler timess, but in the case of the bathroom, the evidence accumulates.
The electric dryer, despite all its convenience and reduction in paper waste, creates a paradox: a device designed for healthcare that may actually facilitate the spread of disease.
