Yes, I'm concerned about bacteria spread by hand dryers, because hand dryers are in bathrooms where there are a lot of germs. A lot of people don't wash their hands properly after using the bathroom and it's very easy for these devices to get very dirty, fast. Most diseases are spread by human contact, so hand dryers are dangerous.
Honestly, I'm all about saving the environment, but I hate hand dryers for a lot of reasons. The risk of bacteria spread from hand dryers is the biggest reason. Public restrooms are not always the cleanest, and I wouldn't want to catch something just because I really needed to use the bathroom.
Not only are hot air blowers less efficient, taking much to long to dry a good percentage of your hands, almost a full minute, the constantly moist environment of a restroom, lends itself to the growth of bacteria in both the air intake and the air outlet nozzle. Studies have reported that when measuring bacteria on just washed hands, paper toweling and cotton continuous looping towels removed an average of 50% of bacteria on hands, while blowers increased bacteria left on hands by over 200%.
Why should I be concerned of bacteria spreading from a hand drier in a public restroom if I just washed my hands with soap. While not all people do wash their hands with soap, it is expected. Hand driers should not be a place of concern for people worried about bacteria.