if it’s true that wiping one’s hands after washing provides the most effective approach to hygiene, then a lot of those air dryers could be improved upon. One obvious upgrade would be simply to introduce a barrier between the hands so they can’t be rubbed against each other when being dried.
Today’s invention is however an integral washing/drying machine made up of an airblade-like hand dryer suspended above a sink. This would have a single aperture big enough to accommodate the forearms, not just the hands.
People wanting to clean their hands thoroughly would insert them through the dryer’s aperture on the way to the sink below. The skin of the hands would be rubbed by the intense downwards airstream, forcing bacteria to the surface so that they could be washed off more effectively when they reached the sink. People could be encouraged to scrub one hand against the other within the airflow by having the fan activated by this specific movement. Waterflow from the taps could be arranged to occur only after a period of this dry scrubbing.
The hands could then be dried as they are withdrawn, in the usual way.
See this economist’s summary of the data, which shows that towels prevail
http://conversableeconomist.blogspot.co.il/2012/12/paper-towels-v-air-dryers.html