Not all that surprising: New Study Shows Restroom Hand Dryers Spread More Germs Than Paper Towel

Well, there is clearly some germophobia behind all of the coverage for this new study published in the Journal of Hospital Infection: Microbiological comparison of hand-drying methods: the potential for contamination of the environment, user, and bystander. by E.L. Best, P. Parnell, M.H. Wilcox.  I have pasted their abstract below:


To compare the propensity of three common hand-drying methods (jet air, warm air dryers, and paper towels) to contaminate the environment, users, and bystanders.


Hands were coated in lactobacilli to simulate poorly washed, contaminated hands, and dried. The investigation comprised 120 air-sampling tests (60 tests and 60 controls), divided into close and 1m proximity from the drying process. Separate tests used hands coated in paint to visualize droplet dispersal.


Air bacterial counts in close proximity to hand drying were 4.5-fold higher for the jet air dryer (70.7cfu) compared with the warm air dryer (15.7cfu) (P = 0.001), and 27-fold higher compared with use of paper towels (2.6cfu) (P < 0.001). Airborne counts were also significantly different during use of towel drying versus warm air dryer (P = 0.001). A similar pattern was seen for bacterial counts at 1m away. Visualization experiments demonstrated that the jet air dryer caused the most droplet dispersal.


Jet air and warm air dryers result in increased bacterial aerosolization when drying hands. These results suggest that air dryers may be unsuitable for use in healthcare settings, as they may facilitate microbial cross-contamination via airborne dissemination to the environment or bathroom visitors.

Anyway – the article has now been picked up by a variety of news sources.  See below for some links:

Love the picture in the NY Magazine article:

Restroom Hand Dryers Spread More Germs Than Paper Towels, Study Finds — WebMD

This is what happened when people who had their hands coated in paint then used the drier.

Overall, as many know, I am driven batty by the rampant and excessive germophobia out there.  However, in this case I think it is useful knowledge to know how different hand drying methods work.  I have always prefered paper towels for many reasons, now a bit more so.   This story reminds me a bit of the work of Norm Pace who has been telling people for years about how showers vaporize microbes in water and in the biofilms on the shower pipes and thus may be contributing to aerosolization of nasty microbes.

One thought on “Not all that surprising: New Study Shows Restroom Hand Dryers Spread More Germs Than Paper Towel

  1. Some response from Twitter

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Jonathan Eisen

I am an evolutionary biologist and a Professor at U. C. Davis. My lab is in the UC Davis Genome Center and I hold appointments in the Department of Medical Microbiology and Immunology in the School of Medicine and the Department of Evolution and Ecology in the College of Biological Sciences. My research focuses on the origin of novelty (how new processes and functions originate). To study this I focus on sequencing and analyzing genomes of organisms, especially microbes and using phylogenomic analysis (see my lab site here which has more information on lab activities).  In addition to research, I am heavily involved in the Open Access publishing and Open Science movements.