I would guess quite a few less than a traditional wind turbine, due to the much smaller potential danger zone and the more concentrated movement noise. I don't have any hard data, though. I kinda doubt that a mall is going to want a potential bird splatterhouse just outside their main entrance, though, so hopefully the mall management did their homework on it. (Never can tell with management.)
Also, not saying they're noisier than a prop-style turbine, just that the sound is radiated over a smaller area.