About 12 years ago there was a beginning study announced for these public hot air dryers. The study was squashed.
It appears that these hot air dryers are the perfect incubator. When at a fast food place, I always grab a handfull of papper towels on the way in. I instruct my kids for the same and let them know why.
In the late 70's these hot air dryers were installed in many new school locker rooms for a full body dry-off. Result? Increase in athletes foot and in strange places of the body. I think that most have been removed by now.