Hand Dryers Are Blowing Bacteria All Over Your Hands

Public restroom always makes us slightly … queasy. They’re just full of things other people have touched, from doorknobs to toilet flushers to the bathroom sink. And you know that not all of those people washed their hands. Good thing you always wash your hands — but nine times out of 10, you then stick them in a bacteria-spreading factory.

If it’s bacteria you’re worried about, hot-air hand dryers are basically the last place you’re going to want to put your hands. According to a study led by  UConn Health, those jets are pulling in bacteria from the bathroom air and blowing it out again all over your hands. The evidence is pretty undeniable. UConn scientists exposed petri dishes to hot air dryers (with no hands involved) in different conditions — some sat undisturbed for two minutes beneath an inactive one, and others were directly exposed to 30 seconds of the hot air. All of the dishes that had sat in peace grew a maximum of one colony of bacteria. But those exposed to a blast from the hand dryer? Most grew about 18 to 60 colonies, and some had as many as 254.

When the researchers installed high-efficiency particulate air (HEPA) filters on the dryers to cut down on the bacteria the devices took in, they produced about 75 percent fewer colonies. It’s kind of obvious when you think about it. That air in the dryer has to come from somewhere, and bathroom air isn’t pristine — lidless toilets have been known to spread bacteria over a 65-square-foot (six-square-meter) area, after all. But at least the experiment with the filters showed that the bacterial colonies aren’t spreading inside the dryers themselves.

Let’s be clear: The study doesn’t say that you’re better off not drying than using a hot-air hand dryer. It’s a lot easier for bacteria to survive on wet hands, and you’re more likely to spread them around that way. Also, most of the bacteria that the team discovered on the dryer-blown dishes were harmless, and those that weren’t were at least benign for healthy people.

Still, if you’ve got hand-drying options, you might want to opt for the less-infectious choice. Paper towels are still on top as far as that goes, ranking the best for both maximum dryness and maximum bacteria reduction. Dispenser options matter too — the automatic paper towel machines that minimize contact with previous users the most will keep your hands the cleanest, while those rolling cloth dispensers where everyone shares the same long towel get you uncomfortably close to the last person’s wet spots.

On the bright side, if you’ve been using hand dryers, you are still a whole lot better than others that don’t even wash their hands. Natural selection will take them out first.

Author: Chikezie Iroegbu