Photo: Rusty Clarke
Public toilets can harbor handfuls of different drug-resistant strains of Staphylococcus, and scientists have also shown that restrooms are teeming with a wide variety of microbes, many from other people's pee, skin, and certain, ahem... body parts.
But when it comes to the question of whether to dry one's hands on a paper towel, or blow them dry under a hand dryer, scientists have struggled to find a definitive answer to which is better for your health. Until now.
A new, independently-funded study of 36 men's and women's bathrooms at the University of Connecticut School of Medicine found that bathroom hand dryers blow tons of bacterial spores around. Researchers holding up test plates to hand dryer air found as many as 60 different bacterial colonies could be blown onto them during a 30-second air dry. Turns out, even though the air coming out of hand dryers is almost perfectly clean, it ends up pushing more nasty bathroom air around than a paper towel.
Lead study author Peter Setlow says his research find is not a shock.
"The more air ya move? The more bacteria stick," he told Business Insider. "And there are a lot of bacteria in bathrooms."
In fact, other scientists have discovered that "toilet plumes" from inside the bowl of a toilet can spray aerosolised faeces as high as 4.6 metres into the air. And blowing more of that pooey air with a dryer around could cause some serious harm, especially for vulnerable populations like the old and the sick.
Setlow himself, a septuagenarian researcher, says he's stopped using hand dryers altogether after completing his independently-funded study. And he's not the only one. The University of Connecticut School of Medicine where the study was done has also started stocking paper towels in all its facilities.
Still, the general public may not need to be so concerned with how they dry their hands, Setlow says.
"If I'm a person whose immune system is suppressed, I wanna minimise my exposure to bacteria," he says, stressing that his own tactic may be most important to keep in mind for seniors and people with compromised immune systems, people who might struggle bouncing back from being exposed to bacteria that, in a healthy person, might not do much harm.
The truth is that most bacteria aren't bad for us. Microbes are essential to life on Earth. They were some of the earliest life-forms, before us oxygen-sniffing creatures even set foot on the planet. Today, they're an essential part of our own immunity. They even interact with and, at times, control our genes, feeding our brains and our nervous system. One New York City geneticist even suggests new parents roll their kids on the floor of the grimy New York subway, because there's some evidence suggesting exposure to a wide array of crawly microbes early-on helps our immune systems grow up strong and healthy.
And besides, just because bathroom air is grosser than other air, doesn't mean you need to be more squeamish about popping a squat than you are about picking up a call. Microbiologists routinely argue that toilet seats are time and again tested and found to be much cleaner surfaces than our cell phones, office desks and restaurant menus.
Given that around 20% percent of people don't even bother to wash our hands at all after we do our business in a public restroom, hand drying may not be the most serious issue in the bathroom, anyway.
Regular, thorough handwashing, especially before eating and after using the washroom is still the number one way to ensure we stay healthy and illness-free, no matter how you may choose to dry off your mitts afterwards.