Far-UVC light (222 nm) efficiently and safely inactivates airborne human coronaviruses

Sci Rep. 2020 Jun 24;10(1):10285. doi: 10.1038/s41598-020-67211-2.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiviral Agents / adverse effects*
  • Betacoronavirus / radiation effects*
  • COVID-19
  • Cell Line
  • Coronavirus 229E, Human / radiation effects
  • Coronavirus Infections / radiotherapy
  • Coronavirus OC43, Human / radiation effects
  • Disinfection / methods*
  • Humans
  • Pandemics
  • Particulate Matter / radiation effects
  • Pneumonia, Viral / radiotherapy
  • SARS-CoV-2
  • Severe acute respiratory syndrome-related coronavirus / radiation effects
  • Ultraviolet Rays / adverse effects*
  • Virus Inactivation / radiation effects*


  • Antiviral Agents
  • Particulate Matter