Using an air dryer keeps hands cleaner than leaving them wet

Aug 09, 2023

Most public restrooms offer paper towels, a hand dryer or a combination of both to dry your hands after you wash.

Many people have heard that air dryers are unhygienic and get germs all over your hands, and countless headlines over the years have spread the claim. Lynn asked VERIFY if the electric hand dryers in public bathrooms are safe to use or if you should skip them altogether.

Is leaving your hands wet or drying them on your clothes more hygienic than drying them with an electric hand dryer?

No, leaving your hands wet or drying them on your clothes is not more hygienic than drying them with an electric hand dryer.

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The Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), Mayo Clinic and Cleveland Clinic all say that you should use a clean disposable towel or an air dryer to thoroughly dry your hands after washing them.

Germs can be transferred more easily to and from wet hands than dry hands, according to the CDC. The Royal Society for Public Health, a UK-based charity for public health education, explains that foreign bacteria struggle to survive on dry skin, but lingering wetness can help them survive.

A 1997 study by medical researchers at the University of Auckland in New Zealand, and funded by a company that produces both paper towels and electric hand dryers, found that the more a hand was dried the less bacteria it left behind on a surface it touched. And this was true whether a paper towel or an air dryer was used.

Some people might try to dry their hands by wiping them on their clothes. But this will likely be less effective at drying your hands, and will almost certainly be germier.

A 2019 study by researchers with the Squina International Centre for Infection Control at Hong Kong Polytechnic University found that far more bacteria remained on hands dried with clothes than hands dried with paper towels or two different types of hand dryers known as warm air dryers and jet air dryers.

The researchers in the study measured the amount of bacteria on people’s hands, then measured the bacteria totals again after people washed their hands with soap and water and then dried them with one of the studied methods of hand-drying.

On average, there was only a 26.5% reduction of bacteria on the palm and an 81.6% reduction of bacteria on the fingers after study participants dried their hands with their clothes. All other methods of hand-drying reduced bacteria by about 90% on both the palms and fingers, according to the study.

“Drying hands on clothes can compromise the benefits of handwashing,” the study’s authors wrote. “The situation may worsen hand hygiene, especially when the clothes are dirty, because the clothing itself could be a source of contamination and compromise the effect of hand washing.”

While it’s clear you should thoroughly dry your hands after washing them, and it’s clear you shouldn’t use your clothes to dry your hands if you can avoid it, public health officials don’t recommend any one particular method with which the general public should dry their hands.

“The best way to dry hands remains unclear because few studies about hand drying exist, and the results of these studies conflict,” the CDC says. “Additionally, most of these studies compare overall concentrations of [microscopic organisms like bacteria], not just disease-causing germs, on hands following different hand-drying methods. It has not been shown that removing [microscopic organisms like bacteria] from hands is linked to better health.”

“Nonetheless, studies suggest that using a clean towel or air drying hands are best,” the CDC adds.

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What do scientific studies say about electric hand dryers?

There are studies about the hygiene of air dryers and paper towels, hence why there are so many articles online about air dryers getting germs all over your hands. But, as noted by the CDC, those studies are less conclusive than the headlines might lead you to believe.

A 2020 literature review by researchers at the University of Arizona’s Zuckerman College of Public Health found 23 studies since 1987 that researched the effectiveness of paper towels, air dryers or both.

But 15 of those studies were funded, at least in part, by private entities, often by paper towel or air dryer companies specifically. For example, five of the studies were funded by the European Tissue Symposium, a trade association for European paper towel producers. Two of the studies were funded by Dyson, which makes electric hand dryers.

Even the literature review itself, which was critical of both studies supporting paper towel use and studies supporting air dryer use, was funded in part by Excel Dryer, Inc, an air dryer company.

One of the few independent studies, a 2018 study funded by Mexico’s National Council of Humanities, Sciences and Technologies, found that hot-air dryers, which is just one type of electric hand dryer, can disperse bacteria already in the bathroom air into human hands.

A researcher who took part in the study noted in a Healthline article that the study did not prove that the bacteria deposited by hand dryers are responsible for disease, and it is unlikely that their findings would be a problem for people with a healthy immune system.

However, another independent study, a 2012 study funded by the Canadian Institute of Health Research, found bacteria on unused paper towels that could recontaminate your hands after you wash them.

So, for now, we don’t know for sure which method of drying your hands in a public restroom is definitely the best. But we do know you can keep your hands the most sanitary by correctly washing them and thoroughly drying them.

Washing your hands correctly — with soap and water for at least 20 or 30 seconds — is far more important to your hygiene than the way in which you dry your hands, said Paul Pottinger, Ph.D., director of the Infectious Diseases and Tropical Medicine Clinic at the University of Washington Medical Center-Montlake, in a Healthline article.

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