Tuesday, April 17, 2018 by Isabelle Z.
Hand dryers are supposed to help you clean up after using a public restroom, but a new study has shown that they actually make you dirtier thanks to their ability to blow particles of feces through the air.
In a finding that is sure to make you think twice before you push that big silver button the next time you’re in a bathroom, researchers from the University of Connecticut discovered that hot air hand dryers actually draw microbes in from the air and then blow them back out again.
In the study, researchers placed plates beneath hand dryers that collected the bacteria that was blown out of the devices for around 30 seconds at a time. They found as many as 200 individual bacteria colonies in the plates, with different shapes, colors and smells. When they placed the plates in still bathrooms, they caught no more than one bacterial landing per plate on average. Repeated tests across dozens of bathrooms yielded similar results. Their findings were published in the Applied and Environmental Microbiology Journal.
They checked inside the hand dryers to determine whether they had microbes building up inside of them, but there weren’t nearly enough bacteria to account for the amounts the dryers were distributing, leading to the conclusion that they were coming from the air in the bathroom.
Every time you flush a toilet without a lid, the flush’s force sends fecal particles flying into the air as high as 15 feet, and they stay there, suspended like an aerosol. When the hand dryers are used, their intake pulls these particles inside, where they are heated up and then sprayed onto your hands as well as other moist surfaces where bacteria then thrive. Some of the pathogens that were spread included Staphylococcus aureus and Clostridium difficile.
The authors wrote in the study’s conclusions: “This suggests another means of C. difficile transmission and one that may not be interrupted by either hand washing or traditional surface decontamination methods. The role of this potential mode of C. difficile transmission is worthy of future study.”
While the researchers noted that HEPA filters can help to reduce the number of these bacteria, they cannot eliminate them entirely. At the university where the study was carried out, paper towels are now also offered in bathrooms. Lead author Peter Setlow said that the elderly and those who have weak immune systems should avoid using these dryers altogether.
These studies are in line with previous ones showing that hand dryers move bacteria from people’s hands into the air and can contaminate freshly washed hands with deposits of bacteria.
It’s a shame that something that is meant to be “green technology” that helps the environment can actually make you sick. If you don’t want to use paper towels, how can you dry your hands in public restrooms without coming into contact with all that extra human waste bacteria? Some suggest waving your hands around quickly and then patting them dry on your clothing. It’s not ideal, but it does carry fewer risks than using hand dryers.
This study is a good reminder that although a solution may be “green”, it is not necessarily good for you.
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