Everyone would agree that it is important to wash your hands after a trip to the bathroom.
Unless you’re using hand sanitizer, this process involves water, which means that you need to dry your hands afterwards.
To dry your hands, you can use:
- Cotton towels
- Disposable paper towels
- An electric hand dryer (usually found in public toilets)
It should be noted that cotton towels are not suitable for public restrooms as they are used by many people and quickly become soggy and unhygienic.
The hot air debate
The debate about the merits of paper towels versus electric hand dryers has been going on for years:
1. Paper towels absorb residual moisture quickly and can be disposed of without risk of cross-contamination. The disadvantages include the environmental impact of paper production, manufacturing, and disposal.
2. Electric hand dryers, on the other hand, use only heated air, leaving nothing to be disposed of. They do however employ electricity, which does have an environmental impact. From a health perspective, the big disadvantage of air dryers is the fact that that large volumes of pressurised hot air can contaminate the environment by spreading pathogens.
A 2012 article involving a literature search conducted on articles reaching back to 1970, concluded that from a hygiene standpoint, paper towels are considered superior to air dryers – and recommended that paper towels be used in places where hygiene is particularly important, like hospitals and clinics.
The debate is however far from over, as a number of independently funded studies published in 2000, found no statistically significant hygienic difference between dryers and paper towels.
What do dryers spread?
A 2016 study was carried out to identify and count the bacterial contamination of hand air dryers in washrooms. Bacteria were isolated from the outlet nozzles of warm air dryers and were found to be relatively numerous in the air flows. Bacterially contaminated air was emitted whenever a warm air dryer was running, even when not being used for hand drying.
The investigation showed that Staphylococcus haemolyticus, Micrococcus luteus, Pseudomonas alcaligenes, Bacillus cereus and Brevundimonad diminuta/vesicularis were emitted from all of the dryers sampled.
The conclusion of the study is that hot air dryers can deposit pathogenic bacteria onto the hands and bodies of users. In addition it was found that bacteria are distributed into the general environment whenever dryers are running and may be inhaled by users and non-users alike.
In another, less formal experiment, Nichole Ward from California in the US posted a photo on her Facebook account of a petri dish full of bacteria and fungi, which she claims she picked up from a hand dryer.
How dangerous are bathroom pathogens?
A 2014 study in the journal of Applied and Environmental Microbiology, in which researchers tracked the microbiomes of four university restrooms, it was found that although people bring a lot of bacteria into bathrooms, when left undisturbed, many of these bacteria quickly perished.
Gut bacteria did very poorly on the cool, dry, barren surfaces of toilets, floors and bathroom fixtures. Skin bacteria showed better survival, however, and some have the potential to be pathogenic. The skin-associated bacterium Staphylococcus aureus for example persisted on bathroom surfaces, but apart from the fact that it is found on many people's skins, this pathogen generally only causes problems when people are immunocompromised or have open wounds.
According to a Live Science article, public toilets might not always be the cleanest, but they're unlikely to pose any threat to your health. Most bacteria that could be dangerous to people perish quickly on barren bathroom surfaces. Also, people's immune systems, in conjunction with hand washing, should take care of the rest.
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