I use a tent in my apt with a charcoal filter and an ozone generator. I cycle the ozone 15 an hour and unplug it when I am in room. Ozone is cheap but it can hurt you, lol, found that out the hard way.
Dude, before growing in your closet make sure you have proper ventilation and heat control. Some strains stink to holy hell and might peel the paint but if you can hook a carbon filter into the vent system you have to make, it will help alot.