To help mother nature by removing paper towels and also presumable reduce the spreading of microorganisms, the hand dryer was created. But as a result, not only air comes out of these machines.

Research released by the University Of Connecticut and Quinnipiac University, show that germs from the bathroom area's enclosed space were swallowed up by the dryers and then spat out on the next person's damp hands.

The researchers carried out a test subjecting Petri dishes to various places in the public toilet. One was exposed to normal bathroom air, the other held under the hand dryers for 30 seconds.

The result might shock you; dishes in normal air had one to no bacterial colony growth, the hand dryers' air dishes produced 18 to 60 colonies per dish. Their conclusion:

"many kinds of bacteria, including potential pathogens and spores, can be deposited on hands exposed to bathroom hand dryers."
Result after use under UV-light

Although every time someone washes down an open toilet, and countless minuscule poo particle and bacteria will be scattered through the air, a normal healthy person has no need to be worried about getting sick. It's actually people, like seniors, with a weakened immune system should avoid using hand air dryers.

Just because the air is full of bacteria floating around, it isn't automatically harmful to you; in fact, microorganisms are absolutely everywhere, the bulk of this mishmash doesn't sicken you. Above all, contact with bacteria contributes to a stronger immune system so your life will be healthier and longer.

Comparable studies in the past have shown that, although hand air dryers potentially are capable of spreading diseases, the odds are not radically higher just because you need to use the bathroom. Jack Gilbert, a microbiologist at Argonne National Laboratory in Illinois reported to Live Science in 2016:

"The restroom isn't that dangerous, the organisms which can grow there have a very low probability of being able to cause an infection."

Earlier research about correlation between bacterial colonies present on paper tissue and hand air dryers, produce no considerable distinction.

The problem arises when people do not properly clean their hands according to Mark Wilcox, Professor of Medical Microbiology at the University of Leeds:

“When people use a jet-air dryer, the microbes get blown off and spread around the toilet room. In effect, the dryer creates an aerosol that contaminates the toilet room, including the dryer itself and potentially the sinks, floor, and other surfaces, depending on the dryer design and where it is sited. If people touch those surfaces, they risk becoming contaminated by bacteria or viruses.”

About using paper towels:

“Jet-air dryers often rely on no-touch technology to initiate hand drying. However, paper towels absorb the water and microbes left on the hands and if they are disposed of properly, there is less potential for cross-contamination."

There are great controversies regarding this subject, no matter how you look at it, it is inevitable to contract microorganisms anyway. But that is no reason you shouldn't be abandoning hygiene. Next time you use the bathroom, remember to sanitize your hands properly.