Lucía Almagro, biotechnologist: "Hand dryers absorb bacteria from the environment."

One of the essential things to do when using public restrooms is to wash your hands afterward, a simple gesture that can reduce the risk of infection and the development of some diseases. It's a gesture that should be repeated as many times as necessary throughout the day , as has been demonstrated in Spain and around the world following the pandemic.

However, as many benefits as we may gain from washing our hands, we may lose them all if we use a hand dryer afterward, as biotechnologist Lucía Almagro points out on social media, which she uses to share her knowledge and give tips, like this one.

The risk of using hand dryers

In a video, Lucía Almagro explains why using certain hand dryers is not the best option if we want to protect ourselves against certain diseases or avoid contagion, and also if we want to keep our hands as clean as possible .

Contrary to what it may seem, those that dry hands using hot air are the least recommended, "there is scientific evidence that explains that they are capable of absorbing bacteria that are in the bathroom environment , accumulating them inside and then releasing them through the air jet, which means that, once you have washed your hands, they become contaminated with bacteria again," he explains while showing which hand dryers he is referring to.

Because when it comes to hand dryers that use air, there are some that work like a sort of dryer, which could be called the "traditional" ones, but there are also more modern ones, those that invite us to place our hands between two jets of air. These are even less recommended, "according to studies, they are the ones that produce the most contamination. In addition to accumulating bacteria, they also accumulate moisture , a perfect medium for them to grow."

These are statements she has sought to support with scientific evidence, although, as she herself acknowledges, "it is somewhat scarce because it is not a matter of life or death, obviously." However, there are some studies that support what she points out: "A study from the University of Connecticut found that hot air dryers can deposit up to 254 bacterial colonies in just 30 seconds of use , while the bathroom air without the dryer on showed barely any bacterial growth."

The best solution for drying your hands

Just because these air dryers aren't the best option doesn't mean we should avoid washing our hands after using the public bathroom —far from it. In fact, Lucía recommends using paper towels . "They've been shown to remove more bacteria and absorb moisture better."

Plus, these towels have an extra advantage: we can use them to open the door before leaving, thus avoiding touching the handle , which is usually not particularly clean. Not all public restrooms offer the option of choosing the healthiest way to dry your hands, so if these types of dryers are the only ones available, she recommends letting your hands air dry on their own .

References

Del Carmen Huesca-Espitia, L., Aslanzadeh, J., Feinn, R., Joseph, G., Murray, TS, & Setlow, P. (2018). Deposition of Bacteria and Bacterial Spores by Bathroom Hot-Air Hand Dryers. Applied And Environmental Microbiology , 84 (8). https://doi.org/10.1128/aem.00044-18