Never trust orbs you see around reflective objects. (Well, I wouldn't recommend trusting orbs in general) Especially in old and/or drafty rooms and buildings. Not to disprove your theory entirely, but it could be dust or dirt or a number of other things disturbed by the activity in a long since dead environment. But I would say never to rule out the possibility in a place like this ; )
While I was in Cuba (extremely spooky place) you could walk through random abandoned places and find chairs everywhere, in the middle of the room, in the middle of an overgrown yard, facing the corners of rooms, but I have to say one of the weirdest finds was one in the middle of an open bay shower....just sitting there. meh....All in all the whole place was sickeningly Session 9. hahaha
technoinfection
Location: Broadacres Hospital Gallery: Meet the Neighbors