I have used ozone generators albeit some years ago now but they do provide an effective way of cleaning the air quality in a room.
I used to work in Clean Rooms where dust and odours could linger so it was imperative that these were kept ultra clean, much cleaner than any operating theatre.
The only thing was you had to clear the room but after a few minutes it was safe to go back into the room.
There is an old method that works for getting rid of stale smells, dog, tobacco, and so on and that's by cutting an onion in half and placing it in the room overnight.
It does work!
