Far-UVC light (222 nm) efficiently and safely inactivates airborne human coronaviruses
Manuela Buonanno, David Welch, Igor Shuryak, David J Brenner, Manuela Buonanno, David Welch, Igor Shuryak, David J Brenner
Abstract
A direct approach to limit airborne viral transmissions is to inactivate them within a short time of their production. Germicidal ultraviolet light, typically at 254 nm, is effective in this context but, used directly, can be a health hazard to skin and eyes. By contrast, far-UVC light (207-222 nm) efficiently kills pathogens potentially without harm to exposed human tissues. We previously demonstrated that 222-nm far-UVC light efficiently kills airborne influenza virus and we extend those studies to explore far-UVC efficacy against airborne human coronaviruses alpha HCoV-229E and beta HCoV-OC43. Low doses of 1.7 and 1.2 mJ/cm2 inactivated 99.9% of aerosolized coronavirus 229E and OC43, respectively. As all human coronaviruses have similar genomic sizes, far-UVC light would be expected to show similar inactivation efficiency against other human coronaviruses including SARS-CoV-2. Based on the beta-HCoV-OC43 results, continuous far-UVC exposure in occupied public locations at the current regulatory exposure limit (~3 mJ/cm2/hour) would result in ~90% viral inactivation in ~8 minutes, 95% in ~11 minutes, 99% in ~16 minutes and 99.9% inactivation in ~25 minutes. Thus while staying within current regulatory dose limits, low-dose-rate far-UVC exposure can potentially safely provide a major reduction in the ambient level of airborne coronaviruses in occupied public locations.
Conflict of interest statement
D.J.B has a granted patent entitled ‘Apparatus, method and system for selectively affecting and/or killing a virus’ (US10780189B2), that relates to the use of filtered 222 nm UV light to inactivate viruses. In addition, D.J.B has an ongoing non-financial collaboration with Eden Park Illumination, and the authors’ institution, Columbia University, has licensed aspects of UV light technology to USHIO Inc.
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Source: PubMed