The efficiency of hand drying is important in preventing pathogen spread, but knowledge surrounding which drying methods contribute least towards contamination of the environment and users has previously been limited.
A study was recently conducted by expert medical microbiologist Professor Mark Wilcox of the University of Leeds and Leeds Teaching Hospitals, and funded by ETS. The study compared different hand drying methods and their potential to spread bacteria from hands into the air.
The results of the study revealed that modern hand dryers designed to improve hygiene actually spread more germs than paper towels in public washrooms.
The tests demonstrated that the airborne germ counts were nearly 30 percent higher around hand dryers compared with paper towel dispensers.
- Bacterial counts in the air close to jet air driers were 4.5 times higher than around warm air dryers and 27 times higher compared with using paper towels.
- Next to the dryers, bacteria persisted in the air well beyond the 15 second drying time, with 48% of microbes still airborne after 5 minutes. Lactobacilli were still detected in the air 15 minutes after hand drying.
- Drying with warm air and jet air driers resulted in widespread droplet release; contamination was found on all areas of the body demonstrating potential for spread and inhalation to other washroom users.
- Airborne bacteria were dispersed one metre away within the first five minutes of sampling and bacteria were found up to two metres away.
Professor Mark Wilcox who conducted the study remarked:
“These driers are effective at drying hands but at what cost?” If you’ve done a cursory male hand wash, wafting your palms under the water, there is likely to still be a high bacteria count on your hands. Next time you dry your hands in a public toilet using an electric hand dryer, you may be spreading bacteria without knowing it. You may also be splattered with bugs from other people’s hands. I do not believe it is sensible to install these in hospitals.”
How were the tests conducted?
The research team contaminated hands with harmless bacteria not normally found in public toilets. The test was conducted to simulate hands that been poorly washed. Subsequently, air samples around the driers and up to 6 ft away were collected. Bacteria counts close to jet air driers were found to be 4.5 times higher than around warm air dryers and 27 times higher compared with using paper towels.
Next to the dryers, bacteria persisted in the air well beyond the 15 second hand-drying time. The bacteria were still detected in the air 15 minutes after hand drying, according to the research published in the Journal of Hospital Infection.
The spread of bacteria and germs in public places, particularly in washrooms is a priority for public health experts. Stories surrounding the spread of infection in the healthcare sector are continually in the newspapers across Europe.
The extent to which jet-air and warm air driers dispel microbes in the washroom environment raises serious questions concerning policy guidance to avoid the spread of infection in hospitals and other public environments. The study findings clearly demonstrate that hand drying with single use towels has the least risk of airborne microbial contamination.
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