I found this "experiment"[1], this is about cleaning/disinfecting a room, by starting an ozone generator in a closed room, keep the ozone level at a certain value for a given time, then switch off the generator and wait at least one hour before re-entering the room:

https://www.ozonetech.com/sites/default/files2/pdf/Ozone_dis...

BTW such a high concentration is likely to affect contents of the room, ozone can accelerate oxydation of most metals and rubber.

[1] it looks like a scientific paper, but it is not AFAIK published and actually comes from the site of a firm making ozone generators, so I would take results about the effectiveness with a pinch of salt, but I don't see how the dangers implied can have been overstated