Odour control is an important aspect of indoor gardening. Since these gardens are usually in small, warm spaces with little ventilation, strong odours of vegetation and nutrients can build up. One of the best ways to ensure grow room odor control is through the use of a combination of exhaust fans, carbon filters, and ozone generators. Exhaust fans are used to force air through the carbon filters, which traps and absorbs the odors. Ozone generators have some disadvantages, including health concerns, but they are excellent at killing bacteria, mold, and mildew.