During the COVID-19 pandemic, one thing was made abundantly clear across the world: Proper handwashing is really, really, important for public health. One important, and perhaps overlooked step in proper hand washing is the last one, the drying step. There are various methods for hand drying, however, some scientists warn that the automatic hand dryers in public bathrooms actually do more harm than good.
Hand Dryers Are A Public Health Nightmare
Drying your hands after washing them is an important step in preventing the spread of bacteria. This is because when your hands are wet, you are more likely to leave bacteria on other surfaces than if they are dry. Wet hands act as a humectant, meaning that the moisture allows bacteria to stick to surfaces more easily. Most public bathrooms offer either paper towels or some kind of automatic hand dryer to dry your hands with. Unfortunately, those super-speed hand dryers that have become more popular over the years are the worst of them all. They are so bad, in fact, that many hospitals have removed them from all of their bathrooms. (1)
In 2014, a University of Leeds research team discovered that no-touch jet dryers in public bathrooms spread bacteria around the bathroom faster even than they dry your hands. Not only that but those pathogens and bacteria continued to float around in the air for up to 15 minutes after use.
The Hospital Experiment
This information is obviously highly important for places like hospitals, where there are vulnerable people as well as resistant bacteria that can be a huge danger to peopleâs health. A group of researchers replicated the Leeds experiment but in a real-world situation. They set up their study in two bathrooms in hospitals in three different cities: Leeds, Paris, and Udine, Italy. In each hospital, one bathroom was set up with only paper towels, the other with hand dryers. They took air samples and swabs of various surfaces every day for four weeks. Next, they took a two-week break when they swapped around which bathroom had the paper towels and which had the dryers. They then repeated the sampling and swabbing as before. The process was also repeated a third time.
The researchers found that the number of bacteria in the air and on surfaces was consistently higher in every restroom where hand dryers were used. Though the bacteria was highest in the Udine bathrooms, it was in the UK bathroom where they found several resistant bacteria.Â
âConsequently, we believe that electric hand dryers are not suited to clinical settings, and, as such, existing (e.g. NHS) infection control building guidance needs to be amended and strengthened,â the research team wrote.
Why So Much Bacteria?
The issue, lead researcher Mark Wilcox says, is because of the lack of proper hand washing in the first place.
âThe problem starts because some people do not wash their hands properly,â Wilcox explained. âIn effect, the dryer creates an aerosol that contaminates the toilet room, including the dryer itself and potentially the sinks, floor and other surfaces, depending on the dryer design and where it is sited. However, paper towels absorb the water and microbes left on the hands and if they are disposed of properly, there is less potential for cross-contamination.â
The slow-drying, warm air dryers donât necessarily blast the bacteria around like the jet-dry versions, but they arenât much better. Paper towel is also not perfect, but bacterial speaking they are much better.
There are other reasons, as well, as to why there is a lot of bacteria in the air in a public bathroom. For example, flushing without putting the lid down releases a fine mist of microbes into the air. These stay in the air for a time and can disperse over an area as large as six square meters. (2)