Hand dryers worse than paper towels for spreading germs

by
in science on (#PBJR)
Researchers have discovered that when hands are poorly washed airborne germ counts are 27 times higher around air dryers in comparison with the air around paper towel dispensers. This shows that both jet and warm air hand dryers spread bacteria into the air and onto users and those nearby. "These findings are important for understanding the ways in which bacteria spread, with the potential to transmit illness and disease," said Professor Mark Wilcox, who led the study.

Researchers collected air samples around the hand dryers and also at distances of one and two meters away. They found that air bacterial counts close to jet air dryers were 4.5 times higher than around warm air dryers and 27 times higher compared with the air when using paper towels. Next to the dryers, bacteria persisted in the air well beyond the 15 second hand-drying time, with approximately half (48 percent) collected more than five minutes after drying ended and still detected in the air 15 minutes after hand drying.
Reply 15 comments

Yes, but (Score: 1)

by Anonymous Coward on 2015-10-03 14:47 (#PBPE)

Are there better alternatives?

Besides, perhaps, single use hand towels.

Re: Yes, but (Score: 1)

by pete@pipedot.org on 2015-10-03 20:18 (#PC9Z)

Waterless hand sanitizer have been around for some time, but leave a weird unclean after-feeling imho; plus i'd imagine there are some people would refuse to use it, leaving the door handle dirtier than the toilet seat :)

Although not an alternative, an improvement could be to use UV light to sanitize the air. I know they are used in some air duct systems, but i'm not sure how efficient or quick they are, particularly for such a high volume of air.

Re: Yes, but (Score: 1, Interesting)

by Anonymous Coward on 2015-10-04 07:56 (#PDA0)

There are a number of studies showing that hand sanitizer is less effective than soap and water, too.

I'm fairly sure I saw this particular study, about hand dryers, back in the mid- to late-1990s, but it showed that several minutes after drying your hands left you with the same levels, regardless of which method you used.

Ultimately, this is only useful for modelling the spread of disease, as most people will not change their hand washing methods anyway.

Re: Yes, but (Score: 1)

by pete@pipedot.org on 2015-10-04 12:42 (#PDSE)

but it showed that several minutes after drying your hands left you with the same levels, regardless of which method you used.
I wonder what the root of that is - the fact that soaps are meant to break free and rinse-off dirt and germs, versus actually killing the germs? Or that people who use jet dryers just suck at washing their hands, in general?

Re: Yes, but (Score: 0)

by Anonymous Coward on 2015-10-05 00:11 (#PF1Y)

This is a good question. I'd also want to know if the location - public toilets, private workplaces, hospitals and so forth - impacts the germ level. So many things to control for, such little time.

Re: Yes, but (Score: 1, Interesting)

by Anonymous Coward on 2015-10-04 09:13 (#PDE8)

In a recent trip to Sydney the pub around the corner from the hotel had an instep on the toilet door to allow for opening the door with a foot. Surprisingly, people actually used it.

Re: Yes, but (Score: 1)

by pete@pipedot.org on 2015-10-04 12:37 (#PDSD)

That is a great idea; Of course it would go without saying that Australians would probably have pub-science down pat :) When I can, I use my used paper towels to grab the door handle, and hope they put a trashcan close by.

Re: Yes, but (Score: 0)

by Anonymous Coward on 2015-10-04 23:50 (#PF19)

Ooh, I'd use that. I hate touching toilet doors because of the number of people who walk off after having a crap who don't wash their hands.

Re: Yes, but (Score: 1)

by bryan@pipedot.org on 2015-10-05 15:59 (#PH6J)

Since they are probably already installed at the front entrance, why not just put automatic sliding doors on the bathrooms?

Granted, you'll probably want either an opaque or frosted glass version. Also, an automatic door (times two for both genders) will surely be more expensive than a standard door.

Re: Yes, but (Score: 2, Insightful)

by evilviper@pipedot.org on 2015-10-06 01:21 (#PJNX)

Depends on why you have bathroom doors in the first place. I've been in airports that eliminate the doors entirely, and just have a partition immediately inside the passageway, so nobody outside can see in. That seems like the best solution in general.

If you still want a door, it might be a small bathroom that needs to lock, or they're for blocking noise, odors, etc. In tight spaces they can be good barriers to keep high-traffic from incidentally pushing in. In any of those cases, automatic doors wouldn't work (and they'd be expensive additions). That is, unless the bathroom door goes directly outside, into the elements...

Not the first 'study' (Score: 2, Interesting)

by tanuki64@pipedot.org on 2015-10-04 11:34 (#PDP8)

Perhaps not as scientific, but more fun to watch:
https://www.youtube.com/watch?v=1pFww_EaLiY

TED - How to use one paper towel (Score: 1)

by pete@pipedot.org on 2015-10-04 12:50 (#PDT5)

There is atad of science behind using papertowel efficiently:

TED talk - https://www.youtube.com/watch?v=2FMBSblpcrc

"Discovered" ? (Score: 1)

by evilss@pipedot.org on 2015-10-04 21:06 (#PES2)

This has been know about for decades. Hell when I was in college in the early 90's one of my intro microbiology labs involved taking samples from the bathrooms, including sampling the air from the hand dryers. It's the reason I skip hand dryers to this day.

Re: "Discovered" ? (Score: 0)

by Anonymous Coward on 2015-10-04 23:52 (#PF1A)

When I was doing a biology class at high school (about 1990) we had to take swabs from any surface to see what would grow. I chose my teeth, and got the sample back a week later.

The teenage genius next to me asked "Don't you brush your teeth? Hurr hurr! Dirty teeth! Dirty teeth!"

This guy went on to work for the (not-United States) government...