Far-UVC (222 nm) efficiently inactivates an airborne pathogen in a room-sized chamber

Ewan Eadie (Lead / Corresponding author), Waseem Hiwar, Louise Fletcher, Emma Tidswell, Paul O'Mahoney, Manuela Buonanno, David Welch, Catherine S. Adamson, David J. Brenner, Catherine Noakes, Kenneth Wood

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)
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Many infectious diseases, including COVID-19, are transmitted by airborne pathogens. There is a need for effective environmental control measures which, ideally, are not reliant on human behaviour. One potential solution is Krypton Chloride (KrCl) excimer lamps (often referred to as Far-UVC), which can efficiently inactivate pathogens, such as coronaviruses and influenza, in air. Research demonstrates that when KrCl lamps are filtered to remove longer-wavelength ultraviolet emissions they do not induce acute reactions in the skin or eyes, nor delayed effects such as skin cancer. While there is laboratory evidence for Far-UVC efficacy, there is limited evidence in full-sized rooms. For the first time, we show that Far-UVC deployed in a room-sized chamber effectively inactivates aerosolised Staphylococcus aureus. At a room ventilation rate of 3 air-changes-per-hour (ACH), with 5 filtered-sources the steady-state pathogen load was reduced by 98.4% providing an additional 184 equivalent air changes (eACH). This reduction was achieved using Far-UVC irradiances consistent with current American Conference of Governmental Industrial Hygienists threshold limit values for skin for a continuous 8-h exposure. Our data indicate that Far-UVC is likely to be more effective against common airborne viruses, including SARS-CoV-2, than bacteria and should thus be an effective and "hands-off" technology to reduce airborne disease transmission. The findings provide room-scale data to support the design and development of effective Far-UVC systems.

Original languageEnglish
Article number4373
Number of pages9
JournalScientific Reports
Publication statusPublished - 23 Mar 2022


  • Air microbiology
  • Antimicrobials
  • Bacteria
  • Civil engineering
  • Influenza virus
  • Lasers, LEDs and light sources
  • Pathogens
  • Public health
  • Tuberculosis
  • Viral infection

ASJC Scopus subject areas

  • General


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