A study suggests that high-speed air dryers are not doing the job well enough when it comes to avoiding contamination.

Automatic air dryers have become to go-to solution for many public washrooms in recent years, and these days are found in all kinds of facilities.

However, they leave up to 10 times the contamination on people’s hands as plain old paper towels, according to a study published in the journal of the Society for Healthcare Epidemiology of America.

That study found that air dryers leave contaminants on poorly-washed hands, which are then frequently spread to clothing and other surfaces.

Researchers in the United Kingdom assessed a variety of hand-drying methods to determine the impact of hand hygiene on the spread of germs.

Study volunteers dipped their hands in a nonharmful viral solution, shook them off without washing, then dried their hands using either an air dryer or paper towels. They took a predetermined path through a hospital, interacting with high-touch surfaces like elevator buttons along the way and wore an apron to test contamination on their clothing.

The results were dramatic.

On average, the levels of contamination found on surfaces was 10 times higher after the volunteers had dried their hands with an air dryer compared to instances where a paper towel was used. The study also found there was greater microbial transfer to the apron when volunteers used the air dryer.

“The study was performed in a healthcare setting and has important lessons for health institutions that still have high-speed air dryers in restrooms,” said one of the study authors, Ines Moura, Ph.D. “But the results are also relevant for public restrooms with high foot traffic.”