State-of-the-art Technology: Inactivation of Pathogens Using a 222-nm Ultraviolet Light Source with an Optical Filter

Introduction Ultraviolet (UV) radiation with wavelength of 254 nm has been widely used for sterilization and inactivating viruses. UV radiation with wavelength of 254 nm can effectively inactivate viruses and bacteria; however, irradiating the human body with such UV light can cause skin cancer and internal disorders. Use of UV irradiation at that wavelength in environments in which people are present has thus been avoided. Even so, UV radiation with wavelength of 222 nm has recently been attracting attention because it has a strong effect in terms of sterilization and inactivating viruses in a similar manner to conventional 254-nm-wavelength UV radiation. As for safety, it has been confirmed by multiple medical institutions and universities that 222nm UV is much safer than the conventional 254-nm UV radiation. If UV radiation were harmless to people, it could be used for sterilization and inactivating viruses in any public and commercial facilities in which people are socially active, such as hospitals, schools, and offices. It is therefore expected to balance the tradeoff between suppressing pandemics and maintaining social and economic activities.