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Medicine Science

Hot-Air Dryers Suck In Nasty Bathroom Bacteria, Shoot Them At Your Hands ( 133

An anonymous reader quotes a report from Ars Technica: Hot-air dryers suck in bacteria and hardy bacterial spores loitering in the bathroom -- perhaps launched into the air by whooshing toilet flushes -- and fire them directly at your freshly cleaned hands, according to a study published in the April issue of Applied and Environmental Microbiology. The authors of the study, led by researchers at the University of Connecticut, found that adding HEPA filters to the dryers can reduce germ-spewing four-fold. However, the data hints that places like infectious disease research facilities and healthcare settings may just want to ditch the dryers and turn to trusty towels. Indeed, in the wake of the blustery study -- which took place in research facility bathrooms around UConn -- "paper towel dispensers have recently been added to all 36 bathrooms in basic science research areas in the UConn School of Medicine surveyed in the current study," the authors note. The researchers speculated that "one reason hand dryers may disperse so many bacteria is the large amount of air that passes through hand dryers, 19,000 linear feet/min at the nozzle. The convection generated by high airflow below the hand dryer nozzles could also draw in room air."
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Hot-Air Dryers Suck In Nasty Bathroom Bacteria, Shoot Them At Your Hands

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  • by whoever57 ( 658626 ) on Friday April 06, 2018 @11:33PM (#56396287) Journal

    I think that the Dyson dryers are the worst. There is usually a small pool of water in the device, just ideal for bacteria to grow in, then the air blows, potentially taking tiny droplets of this bacteria-infected water into your face.

    • by Anonymous Coward

      Once you know how to use them, they're brilliant and don't blow anything your face.

      Take your wet hands, put them down the SIDES of the dryer (not the top!) and bring them into the dryer from the side. Draw them upwards slowly. That's it. The water sheets off the hands downwards and nothing goes upwards. Usually one draw is enough to make them bone dry, if you need to, repeat the in-at-the-side-draw-upwards action a second time.

      DO NOT:
      Stick your hands in the top, thrusting downwards, because the water will s

      • Volatile (Score:5, Interesting)

        by DrYak ( 748999 ) on Saturday April 07, 2018 @03:42AM (#56396823) Homepage

        If you pay attention to the article (yes, I know, /. , never RTFA), the mostly are interested in what is floating in the air.
        As in spores that at some point of time got air born (TFS mentions "flushing" as something that might launch spores in the air)

        The whole idea of the article, is that specifically exposing plates to the air flow of the air dryer gives much more bacteria colonies than anything else (sample the nozzle of a turned off air dryer, leaving the plate in an currently unused toilet room, blowing air with a less powerful small fan, etc.)
        Their proposed explanation is that this contamination is due to the sheer amount of air that goes out of the dryer (there aren't that many microbes in the air, but when the whole atmosphere of the toilet room is cycled and blown to your plate in a few seconds, you're bound to catch a few microboes).

        From that point of view :
          - Dysons have always been louded for their extremely powerful air flow and insanely efficient fan motors. That doesn't help the "blowing the whole room's worth of air to your hand" problem.
          - Dysons have a pool of water accumulating at the bottom, which will get blown at the exact moment when the dryer is used, helping the "getting microbe airborne" a tiny bit (would be as if someone did flush their toilet exactly in sync with a classical dryer, given TFS. Here the pool is smaller, but closer, but the effect should be tiny).
          - Touching the wall isn't a problem (sampling the nozzles of turned off dryer didn't produce much. Again, it's not that dryers are dirty. It's the fact that almost any particule currently in the air will end up being blown on your hands at some point of time in the cycle of these air blowing monsters. Unless dysons have HEPA filters, there's no reason to suspect they are any different from other dryers)
          - The direction where sheets of water flow isn't relevant to the perspective of this study.

        Funnily though, even if TFS reports that paper towel were added to toilet rooms as a consquence of the study, at point during the study did they test the paper towel surface for microbes...

        Tin foil hat ! Conspiracy theory time !! THEY WERE PAID BY THE "BIG SOFT TISSUE" !!!~~

        • by AmiMoJo ( 196126 )

          Mythbusters did an episode where they tested the "toilet aerosol" theory. Okay, it's Mythbusters, not exactly rigorous science, but they found zero evidence for it.

    • Yes! Sespool at the bottom of the Dyson hand dryer creeps me out. I think the strategy is to gross people out so they'll just air dry thus saving paper and electricity.
    • Also the opening for your hands to fit through is narrow add you endlessly bump into the casing of the unit.

      I hate the things

    • I had read about hand dryers years ago, there is a statistic somewhere along the lines of, when you dry your hands with clean paper towels afterwards, it remove a low percentage of other germs and crap that the soap and water didn't get off completely or some crap like that. But when you use the air dryer you add on average 70% more germs and crap because of the recycled air in the bathroom that the hand dryer uses. I forget the exact numbers. But now when I use a public restroom, like home depot which only

  • It's for the environment. You should be happy to sacrifice your health to save the Earth.

    For that matter, why aren't you collecting your poop and taking it home and composting it?


    • Composting public toilets would make more sense, given the economies of scale. Unless they become like music festival toilets... Eww.
    • by lucm ( 889690 )

      It's for the environment. You should be happy to sacrifice your health to save the Earth.

      They did a study about paper towels usage a few years ago. They installed two kinds of trash cans in different public bathrooms; plain ones, and blue ones with the recycling symbol on it. Turns out that people use a lot more paper towel when they see the recycling logo.

      That's always the problem with people. We tend to forget the first part of the "reduce, reuse, recycle" slogan and make up for it by binging on the other two.

      • by Kohath ( 38547 )

        They did a study about ...

        Science is irrelevant. Environmentalism is a religion. They want to "save the Earth", not accomplish anything specific or achievable.

  • by Anonymous Coward

    This isn't new news. Other studies have been done and reported (here too) years ago.

    Back then, in a quandary about what to do about it, I discovered that washing my hands and shaking the water off, they were dry in less than 2 minutes. So as long as the faucet and door allow me to use my elbow to shut off the water and open the door, I'm good.

    Since then I've been pleasantly surprised by the number of places that have automatic faucets. I'm thinking of putting them in at home, too.

    In a future ideal world, th

  • by Fortis McMannus ( 5347257 ) on Friday April 06, 2018 @11:54PM (#56396347)
    There are dangerous germs in and on most things. Our germophobic culture is doing more harm than good in the long run.
    • There are dangerous germs in and on most things. Our germophobic culture is doing more harm than good in the long run.

      And yet cleanliness is something that has caused us to overcome uncontrolled transmission of quite nasty disease. We're not talking about an alcohol swab every time someone looks at you here. We're talking about public facilities with lots of varied traffic bringing in all sorts of nasties.

      I haven't washed my keyboard in about 5 years. But I still don't use Dyson airblade driers that don't look like they are perfectly dry already. There's a difference between being a germophobe and not wanting a bacterial c

  • Measuring flow in Linear Feet Pet Minute? Really?
  • not really new news (Score:5, Interesting)

    by chromaexcursion ( 2047080 ) on Saturday April 07, 2018 @12:00AM (#56396377)
    Various studies have been published on this in the past few years.
    The "sanitary" air driers are anything but. The more powerful they are the worse they are.
    A little wasteful, but paper is better. If people wouldn't use far more than is necessary to dry their hands it would be less wasteful.
    The small waste of paper is far less that one what's used to treat one person's infection.
    Pay me now, or pay me later. Paper towels are less wasteful.
  • by 93 Escort Wagon ( 326346 ) on Saturday April 07, 2018 @12:09AM (#56396407)

    Maybe women's bathrooms are different, but - man, some guys are just pigs.

    I work at a university - so with an above-average educated population - and what I see in the men's bathroom sometimes makes me sick. Guys (not just students - faculty too!) come out of stalls all the time without washing their hands afterwards... but that's not the worst. What's even worse is the guys who come out of the stall, do a quick fake pass through the sink (1-2 seconds max), then paw at the paper towel dispenser.

    You really think the germs spread by an air dryer are worse than the feces being physically deposited on the towel dispenser?

    Plus we used to have the old fashioned kind of paper towel dispensers - the ones with a hand lever. At least with those you could use a forearm or elbow to advance the paper. But now we've got "eco-friendly" dispensers that don't really work 50-75% of the time. When they work, you pull on the protruding paper to get a small section of towel - that's fine. But when they don't work, the only way to get paper is to manually rotate the little disk on the side of the dispenser - something you can't do with anything but your hands.

    • by Anonymous Coward on Saturday April 07, 2018 @12:30AM (#56396463)

      I spent years cleaning bathrooms - the wrong (or overpopulated) degree will do that to a guy. Let me tell you, people always think for some reason that men are disgusting, nasty pigs. Well. I already had a clue from having had a female flatmate in college, but cleaning toilets was a far more abysmally enlightening experience. Let's leave what happens when drunks and druggies get into a toilet, since that'll be horrible no matter their shape or size...

      Men's washroom have droplets from shaking things off too much around the urinal. Once in a while (we're talking per-day here) there'll be a bit of piss on the floor too somewhere.

      Both sexes tend to have people who don't flush and/or don't wash their hands. It's unfortunately pretty even. Same with drug paraphernalia.

      And then, then there's the women's bathrooms. You will never find a more wretched hive of scum and villainy (Obi-wan couldn't have known since he was a man and had never been a toilet-scrubber). First, take all of the problems of a man's bathroom. Yes. All of them. ALL of them. Look at me. Look at me in the eyes. ALL. OF. THEM. Men are not the only ones who piss onto the wall, but at least there was a urinal in the vicinity. Women have no such excuse.
      Now add menstrual artwork. Pads and tampons stuck to the fucking ceiling or 'padding' the doors so to speak. Sometimes things clog and you discover someone in the fancy office has been dumping theirs in the actual "fancy normal house toilet" reservoir and at that point you might need the plumber to come by.
      Add in maybe one stillborn or miscarriage every... probably once a year back where I worked. It was an office, but would be a lot worse for whoever cleans things up over at a walmart or a mall.
      Makeup. On the mirrors, on the dryers, on the toilets, on the floor, it's like a thick incense sometimes and it'll deposit on everything. You don't have dust in women's bathrooms, it's just foundation settling on anything.
      Fake eyebrows (eyebrows?!?), the one time I found a fresh placenta hidden behind one of the toilets, half eaten pizza, condoms, so many condoms (maybe twice as much as the men's), sometimes with the zucchini still inside... trails of blood, dropped "mooncups", vomit, so much more vomit than the men...

      This was in a relatively professional setting mind you. The guys who work at stadiums and other massive public venues I've talked to had that same distant look that you'd expect from someone with severe PTSD from spending years in a war zone.

      • by Khyber ( 864651 )

        Man, I'm having flashbacks of when I had to clean up after ITT in the building they rented. Ho-lee SHIT the women's bathrooms were just utterly awful.

      • This was in a relatively professional setting mind you.

        Professional working girls by any chance?

        Also can someone help me unread something, I don't feel quite right.

      • by Anonymous Coward

        Came here for this. Worked maintenance in high school/college.

        Shit on the seats in an endless cycle. It starts off with, "EWW GERMS R GROSS IMMA HOVER", which leads to shit on the seats, which leads to more animals hovering instead of sitting their asses down like civilized creatures, because "EWWW THERE WAS POOP ON THAT SEAT, IMMA HOVER".

        Blood. Oh god, the blood. Look, I've dated women. I've Hunted for Red October; I've earned my red wings; I've parted the Red Sea. And mere periods don't explain

      • by WallyL ( 4154209 )

        I used to work at a quick service restaurant (read: fast food restaurant), and the women's restroom was normally a little bit dirtier than the men's room. I didn't experience anything quite as extreme as the parent post author, but I did notice the men were not the grossest people in the bathrooms...

    • My Wife assures me the womens bathrooms are infinitely worse. Sometimes to the point where she says you wonders if some just stand over the seat and let all go.
      • by Anonymous Coward

        I'm pretty sure they are finitely worse. And certainly not exponentially worse.

    • by swb ( 14022 )

      I cleaned 6 women's bathrooms in a college dorm, 5 days a week for a couple of years in college.

      I found their toilet habits to be pretty good. The sinks and the shower were hairy, and the sinks often had a lot of makeup residue.

      They also had a habit of puking in the sinks instead of the toilet, which was much harder to clean because you had to scrape the puke out since the sinks had a fairly fine steel mesh over the drains.

      This was in the 1980s at the peak of the Bartles & James wine cooler phenomenon,

  • "I didn’t think it was physically possible, but this both sucks and blows." -Bart Simpson

  • The point of washing your isn't to kill germs. It's to get rid of the places harmful bacteria can live in and multiply in. This applies to not just your hands but hospital floors, walls and hell almost everything. Bacteria are everywhere. If you bleached everything but don't actually remove the stuff the bacteria thrive on, they will be back. If you use anti bacterial hand wash you are really just giving the harmful bacteria an advantage over the good bacteria on your skin. So wash, actually clean and
    • by mentil ( 1748130 )

      If you want to eliminate the possibility of there being harmful bacteria on your hands, you should amputate them. Problem solved. Or install a HEPA filter in your airways; just yank out a section of your throat to replace it, and don't forget to do this before going to sleep.

      • Yeah, what you said. Tidal volume of human lungs (the amount we actually breath in and out per breath) is a bit over 0.5 liters. We breathe 12-20 times per minute, say 16. Thus we breathe in roughly 8 liters of air per minute just being inside a bathroom. A typical bathroom stay is (very roughly) 2 minutes or so if you are only urinating and are male, 4 or 5 minutes if you are urinating and are female (based on observations, not experience), and if you defecate anywhere from 5 to 15 minutes or even long

    • The point of washing your hands is to dislodge a reasonable amount of germs, and perhaps to wash off fecal matter.

      Urine is sterile in most people (but not everyone).

      We encounter a large amount of germs constantly. But we get sick if we are weakened or we don't recognize the signature of the illness so our immune system is slow to react.

  • So spreading bathroom germs is bad, for sure, but we shouldn't give up on air dryers, because paper towels are straight up wasteful on several levels. HEPA filters will reduce the air flow, causing a hand dryer to use _a lot_ more electricity, but a reasonable fix isn't that difficult: bathrooms are already plumbed, so just run another pipe to bring in fresh air--even from a nearby closet would probably be good enough

    • People worry about the oddest things like blowing air, when they ignore handling the door knob or lever with a bare hand which has who knows what on it along with god & I know is on the bottom of the shoe on your foot that you track into your car, home and workplace.

      • Yeah, or what you get owning a dog or cat. Which I do. I laugh at your silly blowing air and its bathroom flora -- do I hold my breath while I'm in the bathroom? Of course not. Do I not pet my dog in spite of the fact that my dog has far more bacteria on it than are being discussed in this article? No, I pet my dog, I snuggle with my dog, my dog licks my very face. Do I grade papers that have been handled by literally hundreds of students while eating a doughnut (and not washing my hands after every

  • Nothing wrong with bacteria.
  • Newsflash: your skin is ALREADY covered in bacteria from your GI tract and all of your household members' GI tracts. Getting several more won't affect anything. It only makes sense in institutional and clinical settings where you might not want to get infected with someone else's bacteria. But that should be easy to fix - just place the laundry room away from lavatories.
    • by PCM2 ( 4486 )

      GI tracts and other people's GI tracts are not the only source of bacteria. Look up "nosocomial" infections. These are the ones that are caused by strains of bacteria that exist in hospitals, institutional and clinical settings (and only there ... you will never find them in your home). Bacteria are everywhere and there are far too many types to be explained by hand dryers.

  • especially the newer ones (Dyson Airblade and its copies) that blast air at high speed (instead of using hot air at low speed). They're bloody loud, and air dryers never manage to get your hands dry within their set time limit. I always seem to have to use them twice (and yes, I shake out my hands beforehand).

  • I hate air dryers and prefer using paper towels for many reasons. Much to my irritation paper towels are becoming rarer and rarer. Most restrooms seem to now only have an air dryer rather than paper towels. I cant stand it as the air dryer makes a loud noise. Also, its a good idea to use paper towels to open the door as you go out (many people do not wash hands and you are touching the same handle they did). There should be a law to require paper towels in all restrooms.

  • Never have liked them. Prefer paper towels that actually DRY your hands instead of having to wipe them on your pants after the stupid hand dryers.
  • Sheldon already told people how bad hot air dryers are []. Apparently the authors of the study simply regurgitated what he said and added a few pieces so it doesn't sound exactly the same.

  • Ya and as soon as i touch the bathroom door handle i get germs as well. walking out the door will stir them up too then OMFG we go outside where gazillions of them float in the air going down our lungs along with fumes from cars,trucks and airplanes,smoke from the chimneys from people who burn fuel oil/wood/coal to heat their homes..guess what, were ALL going to DIE..go cure cancer you will get more funding money that way.
  • by Anonymous Coward

    It would be more sanitary to have a plague-infested gibbon sneeze my hands dry

  • No one has noticed that, invariably, the air blown by one of those blowers is quite hot, surprisingly so. There's a damned hot surface or wire mesh somewhere inside that blower that I suspect is doing a real job on the bacteria flowing through there.

    Surely that has something to do with the problem, ne? Has anyone passed an ordinary Petri dish through the airflow of one of these heaters and then waited to see what grew? That would be a LOT better than all these woeful, disgusting tales about people and di

  • Don't set the intake to the drying from the bathroom. Pull it from a separate vent outside of the bathroom. Not hard to do. Could pull it from the canteen break room now that people aren't allowed to smoke in there anymore.

Competence, like truth, beauty, and contact lenses, is in the eye of the beholder. -- Dr. Laurence J. Peter