Yes, but only when occurring in extremely high concentrations - levels that due to the SafeZone™ Technology, a Biozone® Air Purifier is incapable of producing. The Federal Government and other agencies have set safety guidelines, Ozone concentrations of 0.05 - 0.10 ppm. The Biozone® Air Purifier CANNOT produce higher than 0.05 ppm. Reports and studies that raise questions about the safety of ozone deal with ozone levels at or above the recommended concentrations.