There are some who do seem to breathe a sigh of relief spotting a hot hand air dryer in a washroom. Especially in the absence of tissues or a handkerchief. The convenience of sticking your hands under the bathroom dryer may seem like a convenient and easy way to get your hands dried, but you may not be aware of the bacteria deposit that is present within the machine.
As many studies have shown, these machines would suck up the bacteria present in the washroom air and then deposit them on the washed hands, defeating the purpose of the machine.
Let’s look at why the hot-air hand dryers found in washrooms are a potential source of bacterial infection. The mechanism behind the functioning of a hot-air hand dryer is that it heats up the air in the surroundings and evaporates the water on the hand.
Hot-air hand dryer being an abode for bacteria
In the 2018 study by US researchers – Deposition of Bacteria and Bacterial Spores by Bathroom Hot-Air Hand Dryers, published by the American Society For Microbiology, scientists exposed a transparent flat glass (petri dishes) to bathroom air under different conditions to observe bacterial growth. With the hand dryers off, Petri dishes exposed to bathroom air grew only one colony of bacteria. In contrast, Petri dishes exposed to hot air from a bathroom hand dryer for 30 seconds grew up to 254 bacteria colonies.
The test was repeated to find out whether bacteria was multiplying in the bathroom dryer. A high-efficiency particulate (HEPA) filter was attached to the dryers to eliminate most bacteria from the air passing through them. Bacteria in petri dishes decreased by 75% after being exposed again to hand dryer air. Additionally, there was minimal bacteria on the nozzles of the hand dryers. In their study, most of the bacteria came from the washroom air.
So, how do bacteria seem to remain in the bathroom air? “Every time you flush the toilet, especially with the lid of the commode open, the bacteria present in the toilet is dispersed in the air due to the aerosols from the flush, causing the washroom to be contaminated,” says Dr Mohit Saran, consultant, Internal Medicine, Manipal Hospital, Gurugram, Delhi NCR.
Dr Saran explains that the bathroom dryer tends to suck in the bacteria present in the room. “If a person doesn’t wash hands thoroughly after using the loo, the bacteria in the hands are also sucked in by the hot-air hand dryer and deposit itself there,” he explains. He stresses that the faecal bacteria can remain in the air for a long time if the washroom is not properly ventilated either.
Can hot-air hand dryers pose a health risk?
The use of hot-air hand dryers does not directly cause infections, but they contribute to the spread of bacteria. Because of clamminess, some dryers may harbour bacteria, which then disperse onto hands when used. Dr Saran mentions that there is a relatively low chance of people getting infected through using a hot-air hand dryer. “Contaminated washrooms and not ensuring proper hand hygiene can lead to gastrointestinal infections (from bacteria like E.coli), skin infections, and even urinary tract infections (UTIs), especially in those with low immunity,” he says.
Another variety of hand dryers is the automatic jet hand dryer, which blows air and evaporates the moisture on the hands, which is said to be safer than the hot air hand dryer.
Following proper hand hygiene to avoid infections
The bacteria forming the faecal cloud (faecal bacteria) in the air frequently contaminates washroom floors and walls, so patrons should practice good hand hygiene to be safe from infections. Dr Subramanian Swaminathan, director of Infectious Diseases at Gleneagles Hospitals, Bangalore, says, “Washing your hands after using the toilet and then touching the tap again will leave your hands contaminated, defeating the purpose of washing in the first place. Due to this many institutions are slowly moving to automatic faucets and foot pedal faucets,” he says.
While using the taps with knobs that need to be turned on, Dr Swaminathan says that, after washing hands, one must dry hands and then with a tissue, and then turn off the tap using another tissue and discard the tissue. When you exit the toilet, do the same thing. He recommends using a tissue when touching the handle of the bathroom door, pulling the door, and then disposing of the tissue.
Maintenance of hot-air hand dryer machines
Institutions can reduce bacteria deposits in bathroom dryers by cleaning and maintaining them. “The machine must be cleaned and maintained periodically,” says Dr Swaminathan. He adds that it is important to clean it regularly if it receives a lot of use, according to manufacturer guidelines.
So, should we use hot-air hand dryers? “If you have an option to choose between hot air hand dryers and tissue papers/ handkerchiefs one can choose the latter to avoid infections, ” says Dr Swaminathan, adding that hand hygiene should not be compromised to reduce paper waste. “The World Health Organization (WHO) has issued guidelines on how to wash your hands properly which includes using paper towels. To maintain hand hygiene, tissues are a healthier option,” he says.
Takeaways
- Hot-air hand dryers develop bacterial deposits, sucking in bacteria from public restrooms.
- While flushing, the aerosol spreads bacteria. Not maintaining proper hand hygiene after using the loo can lead to gastrointestinal infections (from bacteria like E. coli), skin infections, and even urinary tract infections.
- Tissues, and reusable handkerchiefs are considered a healthier alternative to hot-air hand dryers.
