by Shane Henson — July 24, 2013—Electric hand-drying machines may be snazzier and better for reducing waste than more traditional paper towels, but according to a recent study by researchers at Queensland University in Brisbane, Australia, they are not necessarily better at hand drying or more hygienic.
For the study, scientists reviewed 12 independent studies comparing paper towels, cloth towels, and hot air dryers. Hand drying effectiveness included the speed of drying, degree of dryness, effective removal of bacteria, and prevention of cross-contamination.
The study revealed, “from a hygiene viewpoint, paper towels are superior to electronic air dryers” and “drying hands thoroughly with single-use, disposable paper towels is the preferred method of hand drying.” It concluded by recommending that the provision of paper towels should be considered as a means of improving hand hygiene adherence.”
When it came to drying efficiency for example, the results indicated that “residual water was more efficiently removed from the hands by cloth or paper towels.” In fact, with just 10 seconds of drying with a single serve towel, the residual water on the hands was reduced to just 4 percent and dropped to just 1 percent with 15 seconds of drying. Air dryers were much slower and required 45 seconds to reduce the residual water to 3 percent. The bottom line: paper towels can generally achieve 90 percent or more dryness with normal use, according to the study’s results.
The study also found that while hand dryers are thought to be better at ridding hands of bacteria, paper towels actually reduced the numbers of all types of bacteria on the hands, and hot air dryers were the least effective method of removing bacteria from washed hands. The results echo others studies that have found that friction is the key component in hand drying as it helps to remove contamination.
Just as startling is the fact that every time a toilet is flushed, a fine aerosol mist can be sprayed into the air. This mist may contain many types of fecal bacteria that can cause diseases. Air movement can encourage the dispersal and transmission of bacteria and increase the chance of cross-contamination.
Used air dryers in washrooms are often contaminated and can emit bacteria in their air flow, so there is a potential risk of persons standing in front of air dryers acquiring the bacteria being dispersed into the air current towards them. The bacteria can then be inhaled or can be deposited on the person’s body or clothes, thus making him/her a potential mobile source of infection. No such spread was seen with either paper or cloth towels, the researchers say.
The review suggests that ultimately paper towels are the best option for settings where infection prevention is critical, such as hospitals and senior care centers.
