Bathroom Hand Dryers: Another Study Shows How Gross They May Be

Want to dry your hands but keep them clean after you've washed them? Those hot air hand dryers in bathrooms may be blowing it. And by it, I mean bacteria and other gunk.

Yet, another study is conjuring up visions of a swirling cyclone of bacteria and other microbes. For a study recently published in Applied and Environmental Microbiology, a team from the University of Connecticut Health (Luz del Carmen Huesca-Espitia, Gabrielle Joseph, Jaber Aslanzadeh, and Peter Setlow) and Quinnipiac University (Richard Feinn and Thomas S. Murray) brought bacteria culture plates into 36 men's and women's bathrooms in an academic health center and exposed these culture plates to the air blown from the hot air driers for 30 seconds.

After this exposure, an average of 18 to 60 colonies of bacteria grew per plate. This included colonies of bacteria that could cause diseases in humans. Compare that to an average of 1 or less colonies per plate when they exposed the culture plate to bathroom air for 2 minutes without the hand dryers running. Installing HEPA (high efficiency particulate air) filters into the dryers did subsequently reduce the amount of bacteria by 4-times but did not remove all of the bacteria that could potentially
cause diseases.

The results of this study don't seem to be just hot air. Other studies have shown similar results. A study published two years ago in the Saudi Journal of Biological Sciences found the following array bacteria from the air flow of fifteen air dryers: Staphylococcus haemolyticus, Micrococcus luteus, Pseudomonas alcaligenes, Bacillus cereus and Brevundimonad diminuta/vesicularis.

Also, a study published in the Journal of Hospital Infection coated study subjects' hands with lactobacilli to simulate poorly washed, contaminated hands, and then had the subjects use a jet air dryer, a warm air dryer, or paper towels to dry their hands. (Yes, shockingly, not everyone really washes their hands well when they use the sinks.) When the subjects used a jet dryer 4.5-times more bacteria was spewed into the air than when a warm air dryer was used and 27-times more bacteria was spewed than when paper towels were used.

Then there's the Journal of Applied Microbiology study that showed that hand dryers could disperse viruses up to 3 meters away (that's almost one and a hYep, that's the crud on hand dryers that's being flung around.

Call me not a fan of hot air hand dryers. If you haven't figured it out, bathrooms aren't the cleanest of environments. Thar be poo in them. And hot air hand dryers really blow. Running such a dryer can be a bit like bringing a leaf blower into a bathroom, sucking in air, bacteria, viruses, and potentially poo and then forcing them out with great speed. Moreover, when a bathroom has no paper towels and just an air dryer, you don't have anything to use to wipe your face, protect your hands when you grab something dirty, or blow your nose (please do not blow your nose with a hot air hand dryer).

While not all microbes being blown around by these dryers are dangerous, the possibility that the dryers are acting as microbe and poo incense machines is a bit disconcerting. Since you spend much of your day rubbing your face, other people's faces, and other things with your paws, good hand hygiene is one of the best ways to prevent catching and spreading infectious diseases. The concern is that hand dryers, especially when they aren't kept clean, may be doing the opposite. And it's not because they are blowing smoke up you know where. Rather, they could be blowing stuff from you know where out there.alf Shaquille O'Neals away).

Follow me on Twitter @bruce_y_lee and visit our Global Obesity Prevention Center (GOPC) at the Johns Hopkins Bloomberg School of Public Health. Read my other Forbes pieces here.

I’ve been in the worlds of business, medicine, and global and public health. And these worlds are a lot more similar and different than you think. Currently, I am an Associate Professor of International Health at the Johns Hopkins Bloomberg School of Public Health, Executive.

Are Bathroom Hand Dryers Sanitary?

Public bathrooms are already a nightmare for anyone who hates germs, and I usually try to just not think about all of the bacteria around me. I cringe when I sit down on a public toilet seat or turn on a faucet, but a new study has me wondering whether I've been worried about the wrong thing all along. If you're wondering whether bathroom hand dryers are sanitary, you should know that a new study found they may spray you with more bacteria than you'd ever think. Researchers at the University of Connecticut analyzed public restrooms and found that hand dryers were dispersing Bacillus subtilis, a bacteria commonly found in human feces. If you're thinking about switching to paper towels permanently, I don't blame you. I prefer hand dryers because they're less messy and, supposedly, better for the environment, but you may also leave the bathroom with bacteria-covered hands. To understand the horrifying results, it's important to know how hand dryers actually work. After you poop, the bacteria can end up aerosolized thanks to flushing, especially because so many public bathrooms don't have lids on their toilets. Some hand dryers recirculate the air in the room, which leads to bacteria ending up on your hands after you wash them. The research team swabbed the hand dryers and didn't find enough germs to account for the bacteria output, according to Live Science, so scientists theorized that bacteria in the air is the cause. The good news is that you aren't likely to get sick from a hand dryer, even though the ick factor is high here. Researchers say the implications of their study are important for health care facilities and other sterilized environments, but most of our immune systems can handle the bacteria that's being blown our way. Adding HEPA filters to hand dryers could be one way to reduce the bacteria that's currently being spread, according to the UConn team. HEPA filters absorb particles and are often found in air purifiers, and the researchers found that bacteria was reduced fourfold after retrofitting hand dryers with the filters. Researchers already suspected that hand dryers were kind of gross. In February, a picture of a petri dish filled with gross-looking spores that were reportedly from a hand dryer got hundreds of thousands of shares on Facebook. A 2016 study found that jet hand dryers — the ultra-modern dryers that blow a lot of air quickly and actually get your hands dry in seconds — spread 1,300 more virus clumps than paper towels, according to Popular Science. But this study provides evidence of how the hand dryers become contaminated in the first place and steps that can be taken to reduce bacteria. So should you switch to paper towels? Like I said, I don’t blame you if you have the urge, but hand dryers are arguably better for the environment. Paper towels end up in the trash, while hand dryers don’t create any waste once they're manufactured, shipped and installed. Still, it’s kind of pointless to wash your hands and have them dirtier than they were when you came into the bathroom, so it’s your choice. Quartz says the findings are most useful for people who work in labs and handle harmful pathogens and healthcare facilities with immunocompromised patients — even though no one wants germs on them, you’ll likely be okay if you’re a healthy adult. And if a bathroom only has hand dryers, you aren’t left with much of a choice. Eventually, manufacturers will catch on and add air filters to hand dryers, but until then, just try not to think about it too much as you’re drying your hands in a public bathroom and use hand sanitizer liberally.