The average person isn't going to have a clean-room setup and we're not looking for perfect here just marginally better when it comes to a bedroom. If you put

The average person isn't going to have a clean-room setup and we're not looking for perfect here just marginally better when it comes to a bedroom. If you put a standard sized air purifier with a HEPA filter in it into a room it will absolutely lower the dirty air of the room. Because over time you're lowering the particle count. If I turn my air purifier on in my room even with the door open the air quality sensors improve their readings quite dramatically.