Abstract Far‐UVC devices are being commercially sold as “safe for humans” for the inactivation of SARS‐CoV‐2, without supporting human safety data. We felt there was a need for rapid proof‐of‐concept human self‐exposure, to inform future controlled research and promote informed discussion. A Fitzpatrick Skin Type II individual exposed their inner forearms to large radiant exposures from a filtered Krypton‐Chloride (KrCl) far‐UVC system (SafeZoneUVC, Ushio Inc., Tokyo, Japan) with peak emission at 222 nm. No visible skin changes were observed at 1500 mJ cm −2 ; whereas, skin yellowing that appeared immediately and resolved within 24 h occurred with a 6000 mJ cm −2 exposure. No erythema was observed at any time point with exposures up to 18 000 mJ cm −2 . These results combined with Monte Carlo Radiative Transfer computer modeling suggest that filtering longer ultraviolet wavelengths is critical for the human skin safety of far‐UVC devices. This work also contributes to growing arguments for the exploration of exposure limit expansion, which would subsequently enable faster inactivation of viruses. Far‐UVC is being heavily promoted as an important tool for the inactivation of SARS‐CoV‐2 in occupied spaces. While there is extensive laboratory evidence of efficacy and safety, there is little real‐world information on whether this technology is “safe for humans.” In this study, a single individual is exposed to extreme doses of filtered far‐UVC radiation, several hundred times the current exposure limit values. At the highest dose, (approx. 780 times the limit value) transient coloring was observed but no visible reaction was seen at 65× the exposure limit. Filtering longer wavelengths appears important for safety of this technology.
【초록키워드】 viruses, Laboratory, SARS‐CoV‐2, ultraviolet, inactivation, Research, Japan, Efficacy and safety, skin, information, change, Critical, Evidence, dose, Tokyo, Radiation, while, wavelength, highest dose, limit, extreme, occurred, appear, contribute, faster, promote, Type, resolved, promoted, filtered, Inc., 【제목키워드】 exposure to,