Ozone generators, "air cleaners," or "air purifying" devices that produce ozone should not be used in the home. Ozone is a gas that can cause health problems including irritation of the eyes, nose, and throat, asthma attacks, and breathing difficulty.
For more information about ozone generators please see http://www.epa.gov/iaq/pubs/ozonegen.html
For general information about indoor air quality, please visit EPA's Indoor Air web site at http://www.epa.gov/iaq/
The California Air Resources Board also has helpful information about ozone generators and other air cleaners:
For more information about ozone, including health effects, see http://www.epa.gov/air/ozonepollution/