It might be hard to believe, but washing your hands is a relatively recent phenomenon. The 19th-century Hungarian doctor Ignaz Philipp Semmelweis is known as the pioneer of the practice—and when he first introduced the idea, his fellow doctors ridiculed him. Today, hand washing is widely seen as a health necessity, and its benefits are supported by an abundance of scientific studies.
Hand drying is the final step in the CDC’s guidelines for proper hand hygiene, but its benefits haven’t been studied as extensively. Scientists agree that it deserves more attention. Why?
Damp hands can spread germs.
Damp hands don’t just get water everywhere. They also provide an ideal environment for microorganisms, and can transmit up to 1,000 times more bacteria than dry hands. That’s a problem, since even the cleanest-looking restroom can contain microscopic particles, including bacteria and viruses, in the air and on surfaces. And here’s a dirty little secret: Most of us don’t dry our hands properly. One study, for example, found that 70 percent of people failed to wash and dry their hands properly before handling food.
For the sake of public health, everyone should dry their hands well. But how should we do it? Until the early 20th century, cloth towels were the only game in town. Since then, we’ve had two main options: hand dryers and paper towels.
And Now A Brief Recent History of Drying Your Hands
The Scott Paper Company develops the first restroom towel, originally called the Sani-Towel.
Airdry Corporation patents the earliest hand dryer, known as the “electric towel.”
The first push button warm-air hand dryer hits the market.
McDonald’s installs warm-air hand dryers in all its US restaurants.
Dyson introduces the Airblade™, a touchless jet dryer that uses high velocity air instead of hot air evaporation to remove water.
TODAY, THE WORLD IS FULL of both paper towels and hand dryers, including warm air dryers and the quick-dry jet dryer models. In many public restrooms, we have our choice of hand drying method. There are important—but often overlooked—differences between them when it comes to hygiene, cost, and environmental impact.
So you’ve just washed up.
These are your drying options:
Up to 6x more bacteria than you started with.
- Wiping on your clothes is the least effective method of removing bacteria from washed hands.
- Dirty clothing can be a source of contamination.
- One study found drying on your clothes can result in a six-fold increase in bacteria on your hands.
7.4 Billion pounds of tissue waste in 2015.
- Using more than one paper towel reduces the amount of bacteria on your hands, but it comes with a high cost for facilities and the environment. In 2015, the U.S. generated more than 7.4 billion pounds of waste consisting of paper towels and other “tissue” materials.
- When dispensers are empty, you have no way to dry your hands, which creates hygiene issues.
- Some people throw paper towels in the toilet and clog the pipes, which clogs sewers and can overwhelm wastewater treatment facilities.
Up to 70% of people likely do not end up with adequately dry hands.
- Warm-air hand dryers can take up to 45 seconds to reduce residual water on your hands to 3 percent.
- One study found that 70 percent of people report spending less than 20 seconds using hand dryers, which means they’re unlikely to dry their hands thoroughly with a warm-air dryer.
- If you leave the hand dryer before fully drying your hands, you risk spreading germs.
Up to 40% reduction of bacteria on hands with the use of one jet dryer.
- High airflows create fast dry times, typically less than 20 seconds.
- Reduced dry times can lead to improved energy efficiency and lower energy costs.
- One independent study found that jet hand dryers are the most effective method for removing bacteria from your hands. One jet dryer, the Dyson Airblade, reduces bacteria by up to 40 percent when used correctly.
THERE’S A LOT of debate out there about which hand drying method is most effective—and that’s a good thing. It shows that we’re all invested in hygiene and public health. But there’s a lot of misinformation as well. Some scientific studies on hand drying aren’t conducted under conditions that simulate real life. (Researchers in one study, for instance, coated their gloved hands with an unrealistically large amount of bacteria , and then didn’t wash their hands before drying.) To make the best decisions for our health, we need reliable data.
Hand Drying Hygiene: What’s fact, and what’s myth?
Hand dryers aren’t all alike. Some are faster. Some are slower. Some use purified air. Some don’t. Which qualities make your hands cleaner? Take this quiz to find out.
Some hand dryers disperse dirty air, but those that come with HEPA (High-Efficiency Particulate Air) filters don’t. HEPA filters capture 99.97 percent of particles as small as 0.3 microns in the air, which is why hygiene testing laboratories require dryers have HEPA filters.
Many hand dryers are slow, which means many users may give up before their hands are dry. To be certified as hygienic by NSF International, a hand dryer must dry hands in 15 seconds or less. Dyson Airblade hand dryers have a 10- to 14 second dry time.
A study that analyzed the amount of airborne bacteria following different hand drying methods found “no significant evidence of any difference” between a Dyson Airblade dryer and paper towels.
WE COULD COLLECTIVELY be doing a lot better at keeping our hands clean. But making that change isn’t just an individual’s responsibility. To ensure we’re washing—and drying—our hands properly, we all need access to fast and hygienic tools. Now more than ever, it’s time to start asking for them.
