Its used as a disinfectant. Like Sir said. If you go in a room with it on your eyes will start to burn and it can burn your lungs pretty bad. The good thing is it only has a 15 minute half-life. So if you set it on a timer or something and turn it off, you can wait 15 minutes and you would never know it was there.
The best way to use an ozone generator is with a charcoal canaster/ carbon scrubber whatever. You set up the canister in the room (middle ish) and connect the exhaust hose leading to the attic. Once in the attic you take a big rubbermaid box (any nice size box will work) and connect the exhaust hose to one end of the box. Thats called a tumble box. Connect another 25 feet of hose to the other end and try to take it to the exhaust fan on the roof. You know the little thing that spins when the wind blows.
Another good thing about ozone is if you do put it in your grow room then it supposed to kill all your pest. You will have to get a pretty big one if you dont have a charcoal canister. Even then you will probably still smell some traces. The best and safest way is the way I described above.