25

A hand drier is a warm and humid environment that is surrounded by bacteria from all the bathroom users. It is claimed that this is one of the main causes for spreading bacteria/microbes (NCBI ref)

Is this claim truly accurate, and should hot air hand dryers be avoided?

  • 1
    You also need to ask, if the likelihood of someone washing their hands changes pending on the drying methods provided? And how often do paper towels run out and not get replace, resulting in less hand washing.... – Ian Ringrose Apr 18 '16 at 12:30
20

Cleaning your hands

The UK NHS has a write up of a 2012 review of the evidence in Mayo Clinic Proceedings. They note that the papers reviewed reported different results, probably due to factors such as the type of hand drier and washing and drying techniques. The review concludes:

Most studies have found that paper towels can dry hands efficiently, remove bacteria effectively, and cause less contamination of the washroom environment. From a hygiene standpoint, paper towels are superior to air dryers; therefore, paper towels should be recommended for use in locations in which hygiene is paramount, such as hospitals and clinics.

But the NHS notes that:

However, if you have no choice – as is the case in most public toilets and workplace washrooms – and only hot air dryers are provided, take extra time to dry your hands thoroughly. There is little evidence that they are any worse than hand towels, other than the extra time spent drying your hands.

(The NHS's advisory body NICE has extensive guidelines on hand-washing and recommends the use of paper towels.)

Contamination

The NHS also has a write up of a 2014 paper in The Journal of Hospital Infection comparing the contamination from paper towels, warm air dryers (as represented by a Pro-Elec GSQ250B) and jet air dryers (as represented by a Dyson Airblade). It found that "Jet air and warm air dryers result in increased bacterial aerosolization when drying hands", with the jet air dryers being worst and paper towels the best. A 2015 paper in the same journal, 2016 paper in The Journal of Applied Microbiology and a 2018 paper in Applied and Environmental Microbiology (see story in Ars Technica) obtained similar results.

The Guardian has an industry perspective of the modern hand dryer design.

  • I wonder if there's any difference between the majority of hand dryers and the ones made from Dyson that create a thin air stream and collect the water at the bottom. Most of the hand dryers out there just blast the hands with a jet of air and spray the water all over the floor, which I always have thought was kinda nasty. – Ravenstine Nov 16 '15 at 19:38
  • 1
    The 2014 Journal of Hospital Infection paper tested a Dyson Airblade as representative of jet air dryers, and found it worse than the warm air dryer. But it didn't compare that against other jet air dryers and only tested one warm air dryer (Pro-Elec GSQ250B). More data would be useful here. The Dyson is more "contained" but it's possible that that's worse rather than better! – Ben C Nov 17 '15 at 20:23
4

According to a recent research paper, "Evaluation of the potential for virus dispersal during hand drying: a comparison of three methods", jet air dryers are the "worst", while warm air dryers are similar to paper towels.

enter image description here

3

This paper found that air-blower hand driers were much worse than paper towels. The Dyson Airblade is a particularly bad offender.

Update: now it turns out that air-blower hand driers also suck in bacterial spores from the surrounding air and blow them on to your nice damp hands. Hand driers should have HEPA filters to prevent this.

  • 7
    That study reached its conclusions by having subjects dip gloved hands in a viral solution and then dry them using one of several methods. The only conclusion that can be reached from this study is that air driers are, indeed, capable of blowing viruses significant distances. This doesn't mean, however, that they're necessarily less hygienic than paper towels for their intended use, since typical usage involves washing hands with soapy water before using any drying method. – Mark Apr 21 '16 at 14:04
  • 1
    @Mark Typical usage isn't necessarily typical. I've seen people in wave their hands under the water for mere seconds, no soap, and then proceed to dry them. That's not rare in my experience. – Wayne Conrad Nov 8 '18 at 18:02
-1

A number of studies have shown that yes they do, although the significance of the amount spread is disputed
http://www.medscape.com/viewarticle/836223
There was also a Mythbusters episode that covered the issue, Down and Dirty/Earthquake Survival 15 May 2013. In this episode they actually tested for bacteria spread by the hand dryer vs paper towels. The results indicated the dryer spread bacteria.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .