"These results indicate that many kinds of bacteria, including potential pathogens and spores, can be deposited on hands exposed to bathroom hand dryers, and that spores could be dispersed throughout buildings and deposited on hands by hand dryers", the authors said. These sterile plates were then cultured and 18 to 60 colonies of bacteria were found to grow on them. There was bacteria contamination inside the hand dryers, waiting to spread to the next person who dries their hands with them.
Another might be because they don't want to use toilet roll to dry themselves because that's disgusting. The results were published this month in the journal Applied and Environmental Microbiology.
While we might hope bathroom hand dryers are helping to clean and dry our hands, a new study has suggested that they are in fact covering them in poo.
Scientists studied three different bathrooms in the University of CT by placing special plates beneath the dryers for 30 seconds. While the study mainly looked for the lab-engineered bacteria, observation did show that pathogens like Staphylococcus aureus, which can cause skin infections, pneumonia, and sepsis, also were found in the bathrooms.
This sends faecal particles into the air, where they linger until you turn on the hand dryer.
What's unclear, they admit, is just why the air-blasted plates showed so many more spores.
Regardless, as Newsweek reported, study author Peter Setlow prefers paper towels, which are now stocked at all 36 bathrooms used in the study.
Some hand dryers like those made by Dyson do use HEPA filters. Researchers recommend placing HEPA filters on all hand dryers to help reduce the harmful bacteria, or just use paper towels, although that's not a favorable option for the environmentally conscious.