Hand Dryers vs. Paper Towels - A Microbiologist's Perspective

The debate of our lifetime, no the 21st Century is raging!! Well, maybe not, but it's still an interesting microbiological question. Here's what you should know.

First off, don’t Google “hand dryers versus paper towels”. The manufacturers/retailers of both systems have bought up all of the search results and flood the search page with dubious, self-serving (self-profiting) websites and YouTube videos that look scientific, but aren’t. This is common for health- and food-related topics on the internet. Go to a reputable source of edited, peer-reviewed scientific publications, like PubMed, a website run by the US National Library of Medicine at the National Institutes of Health. This is where taxpayer-funded medical research conducted at universities, colleges, and the National Institutes of Health is posted in online publications.

The best review article available on this topic was published in 2012 in the scientific journal Mayo Clinic Proceedings. It reviewed 41 years of publications (1970-2011) that compare these 2 methods of hand drying. But before we discuss the most efficient method, let's address the main question:

Why should you wash your hands? Good question. Short answer - because humans are filthy. Our dirty little hands can spread diseases, like the flu virus, Staphylococcus bacteria, E. coli bacteria, and many others. A famously grimy person, Typhoid Mary, spread typhoid fever throughout 1930’s New York infecting at least 51 people and killing 3. The cause? She was a typhoid bacterial carrier (Salmonella enterica serotype Typhi) and did not wash her hands before she handled food as a professional cook. YUCK!! Even without antibiotic treatment, proper hand sanitation and general personal hygiene could have gone a long way to mitigating the problem. 

We all think we know how to wash our hands, but many of us don’t. Let’s talk.

3-step hand washing for adults who don’t want to be gross, disease-carrying Typhoid Marys:

Step 1. Washing: Wash your hands and wrists with soap and warm water. Soap is the most important part to this whole hand cleaning process. Only rinsing your hands without soap does more harm than good. Wet, germy (I think that’s a word?) hands spread bacteria and viruses more than dry hands. Plain old soap will do and no you do not need to scrub up to your elbows like you’re going to be performing brain surgery. No fancy antibacterial soaps are required and may be so harsh that they dry and crack your skin, potentially exposing you to more infections, not fewer. Hand sanitizers have that same risk. If you are worried about the cleanliness of your paws, go wash the grubby things with warm, soapy water! It takes like 1 minute out of your epic life.

Step 2. Drying: Dry your wet fists with 1 paper towel. Just 1 paper towel will do, if you shake your now clean hands over the sink to remove excess water. Paper towels are more effective than hot-air dryers, as I will discuss below. But if you can’t get your mitts on 1 paper towel, then use the second-rate hot-air dryer. It’s better than not drying, vis-à-vis the wet hands spreading germs, blah, blah, blah. The trick that most budding Typhoid Marys don’t do, and the main reason hot-air dryers come in second place, is time. You’ve got to spend like 45 grueling seconds under that hot jet stream to get your metacarpi dry enough to be, well, dry, and not wet or damp. With that thing blasting away like a 747 jet engine, 45 seconds feels like days, but hang in there hero. Rubbing your hands doesn’t help much, but if your bored in your new eternity that is the hot-air dryer experience, go for it.

Step 3. There’s a 3rd step?! Yes, it’s called “Exiting the bathroom without getting disgusting germs all over your now pristine phalanges!”: If the door open outward, use your foot to gently push the bathroom door open. Your shoes are dirty anyway. If the bathroom door opens in, use that 1, now wet paper towel in your hand to open the bathroom door and exit without touching anything. Dump that paper towel in the trash, not in your pocket, ASAP. Ever wonder why many bathrooms don’t have doors, like at rest stops? Door handles, especially bathroom door handles, are the nastiest things ever! The technical term is cross-contamination. Clean digits opening a bathroom door = disease-covered digits!

When do I wash my hands? At a minimum, wash your hands before handling food, after handling any raw meat, before a visit to the bathroom, and after a visit to the bathroom. Before I go to the bathroom? Yes. Cross-contamination goes both ways. Every wonder where bladder infections come from? Dirty hands!!

So in all seriousness, why paper towels? Paper towels dry, really dry, our hands a lot faster than hot-air dryers plus the friction of the paper towel on our skin helps remove any leftover microbes from our hands. And hot-air dryers? One, they take too long for the average person to achieve the same dryness (>4X as long) and there is no friction. Also, there are concerns that that the hot air being blown all over our now sanitized hands is contaminated with the same microbes we just washed off with soapy water (cross-contamination). Hot-air dryers don’t vent in fresh air from outside of the bathroom to blow on our hands. They recycle the same air that just floated over that toilet (ugh!).

Read the Mayo Clinic Proceedings article HERE. 

Huang, C., Ma, W., Stack, S. (2012). The Hygienic Efficacy of Different Hand-Drying Methods: A Review of the Evidence, Mayo Clinic Proceedings, Volume 87, Issue 8, pp. 791-798, ISSN 0025-6196, http://dx.doi.org/10.1016/j.mayocp.2012.02.019.