A study on the effectiveness of ozone in combating airborne viruses was published on the US National Library of Medicine National Institutes of Health government portal. This study was designed to test the effectiveness of air treatment with ozone controlled relative humidity for inactivation of airborne viruses. Four phages (φ174, PR772, MS2 and φ6) and one eukaryotic virus (rodent norovirus MNV-1) were tested for low ozone concentrations (1,23 ppm in phages and 0,23 ppm for MNV-1) and various relative humidity levels with 10-70 minutes of penetration times. The inactivation of the investigated micro-organisms was then studied to determine which of the conditions under consideration was most likely to decrease their infectiousness.
At least two magnitude inactivation was achieved with 40 minutes of ozone exposure at 85% relative humidity for the tested φ174, MS2 and MNV-1. For PR772 and φ6, with a relative humidity of 20%, yielded the same results with a penetration time of 10 minutes. These results suggest that ozone in low concentrations is also an effective disinfectant for airborne viruses when combined with high relative humidity, so air treatment can be carried out in hospital rooms with natural ventilation.