I have an air purifier that operates with a cyclone separator. I had my doubts about it working very well before I bought it, but I must say that I have been pleasantly surprised by it.
The separator traps a lot of dust, hair, and dander. I can actually feel the air getting fresher as it works. I keep it in my bedroom, and I can sleep better with it on. It traps things that cause my allergies to flare up, so I don’t have to deal with sneezing and congestion while trying to fall asleep.
It makes a slight whirring sound, but it doesn’t keep me awake. I would compare the sound to that of a fan.