Washing hands with soap and water is an incomplete process without the final step of thorough drying. Proper hand hygiene requires the removal of moisture, which is just as important as the initial cleansing action. When hands remain damp, they can transfer bacteria to surfaces and people far more easily than fully dry skin. Studies have shown that wet hands may spread up to 1,000 times more bacteria than dry hands, making effective drying a non-negotiable step for infection control. This final action reduces the risk of cross-contamination onto common surfaces after leaving a washroom.
Defining the Tools for Hand Drying
In public and commercial settings, two main types of devices are commonly encountered for drying hands: paper towels and electric air dryers. Paper towels operate on a simple mechanical principle, combining friction with the material’s natural absorbency. Users rub the paper against their skin, physically wiping away water droplets and any remaining microbial contaminants.
Electric air dryers rely on blowing air across the hands to encourage water evaporation. Traditional warm air dryers use heated air at a lower velocity, a process that often takes a significant amount of time. A newer category is the high-speed jet air dryer, which uses a narrow, powerful stream of unheated air, often referred to as an “air knife,” to physically shear the water off the hands. These different mechanisms result in notable variations in hygiene performance.
Comparative Efficacy: Hygiene and Speed
The choice of drying method profoundly impacts hygiene, particularly bacterial removal and the potential for environmental contamination. Scientific research consistently demonstrates that paper towels are the superior option for maximizing hygiene, especially in settings where infection control is paramount. The friction provided by a paper towel physically dislodges and removes bacteria that may have survived the washing process. This mechanical action is not replicated by air dryers.
Jet air dryers and warm air dryers introduce the variable of air turbulence, which has negative hygienic consequences. High-speed jet air dryers aerosolize water droplets and residual microbes, dispersing them into the surrounding environment. Studies indicate these droplets can travel up to 6.5 feet, contaminating washroom surfaces and air. This dispersion contrasts sharply with paper towels, which contain the microbes within the disposable material.
Speed and Compliance
Jet air dryers have been found to disperse significantly more germ particles into the air than paper towels, making them a concern in environments like healthcare facilities. Traditional warm air dryers perform poorly due to the length of time they require, which is often around 30 to 45 seconds for effective drying. This extended time frequently causes users to stop early, leaving hands damp, or to rub their hands together, which can actually bring subsurface bacteria to the skin’s surface.
Paper towels and high-speed jet air dryers are comparable in speed, both capable of achieving a high degree of dryness in about 10 seconds. However, this speed advantage in jet air dryers is offset by the risk of microbial dispersion. Because quick drying encourages higher compliance with the full hand hygiene process, paper towels offer the best balance of speed, physical bacterial removal, and minimal environmental contamination.
Addressing Shared Cloth Towels in Home Settings
While public washrooms offer disposable paper or mechanical dryers, the home environment often features a shared cloth hand towel, which presents unique hygiene risks. Cloth towels easily retain moisture, especially in a humid bathroom, creating an ideal breeding ground for bacteria and fungi. The warmth and dampness allow microorganisms to multiply rapidly.
Each time a person uses a shared, damp towel, they deposit residual bacteria and skin cells onto the fabric, which are then transferred to the next user. This cross-contamination can transmit various pathogens, including gastrointestinal bacteria like E. coli and Salmonella. Fungi that cause conditions such as athlete’s foot and ringworm can also spread through a contaminated cloth surface.
To mitigate these risks, experts recommend using dedicated hand towels for each person in homes with multiple occupants. Color-coding or personalized labels can help ensure individuals use only their own towel. Alternatively, disposable paper towels offer a hygienic, single-use solution. Cloth hand towels should be washed frequently, ideally every few days, to prevent microbial buildup.