Well in a small space I would put a UV filter on the intake to kill nasties before they enter and a carbon scrubber on the exhaust to take care of odour. I would not put an ozone generator inside a closet as you will damage your plants, or at least the portion if the plants close to the ozone generator (I know because I've done it). If your cabinet is in a seperate room that's not frequented by family/pets then an ozone generator is not a bad idea as it will help sanitize the room including removing any odour not otherwise neutralized.
Just to further dissuade you from using ozone generators;
http://www.epa.gov/iaq/pubs/ozonegen.html
Manufacturers and vendors of ozone devices often use misleading terms to describe ozone. Terms such as "energized oxygen" or "pure air" suggest that ozone is a healthy kind of oxygen. Ozone is a toxic gas with vastly different chemical and toxicological properties from oxygen. Several federal agencies have established health standards or recommendations to limit human exposure to ozone. These exposure limits are summarized in Table 1.
Table 1. Ozone Heath Effects and Standards
Health Effects Risk Factors Health Standards*
Potential risk of experiencing:
Decreases in lung function
Aggravation of asthma
Throat irritation and cough
Chest pain and shortness of breath
Inflammation of lung tissue
Higher susceptibility to respiratory infection Factors expected to increase risk and severity of health effects are:
Increase in ozone air concentration
Greater duration of exposure for some health effects
Activities that raise the breathing rate (e.g., exercise)
Certain pre-existing lung diseases (e.g., asthma)
The Food and Drug Administration (FDA) requires ozone output of indoor medical devices to be no more than 0.05 ppm.
The Occupational Safety and Health Administration (OSHA) requires that workers not be exposed to an average concentration of more than 0.10 ppm for 8 hours.
The National Institute of Occupational Safety and Health (NIOSH) recommends an upper limit of 0.10 ppm, not to be exceeded at any time.
EPAs National Ambient Air Quality Standard for ozone is a maximum 8 hour average outdoor concentration of 0.08 ppm (see - the Clean Air Act -
www.epa.gov/air/caa/title1.html#ib)
