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

TY - JOUR

T1 - Far-UVC (222 nm) efficiently inactivates an airborne pathogen in a room-sized chamber

AU - Eadie, Ewan

AU - Hiwar, Waseem

AU - Fletcher, Louise

AU - Tidswell, Emma

AU - O'Mahoney, Paul

AU - Buonanno, Manuela

AU - Welch, David

AU - Adamson, Catherine S.

AU - Brenner, David J.

AU - Noakes, Catherine

AU - Wood, Kenneth

N1 - Funding Information: We would like to thank all the manufacturers who have loaned or gifted us Far-UVC lamps. These contributions have been made without any interference or influence on the research undertaken and without financial contribution. We acknowledge the financial assistance of the United Kingdom’s Department for Health and Social Care (2020/092). We also acknowledge the assistance of Camilo Penaloza for the 3D image used in Figure b and Andrew Collier Cameron and Keith Horne for discussions on data analysis. Funding Information: EE, WH, LF, ET, PO’M, CA and KW declare no competing interests. DJB and other coinventors have a granted US patent entitled ‘Apparatus, method and system for selectively affecting and/or killing a virus’ (US10780189B2). Columbia University (the parent institution of DJB, DW and MB) has licensed aspects of filtered UV light technology to USHIO Inc, and has received a research gift from LumenLabs, a company producing Far-UVC sources. CN has received funding from EPSRC, HM government and the Department for Health and Social Care for projects on COVID-19 transmission and mitigation, and she is a member of the UK government Scientific Advisory Group for Emergencies (SAGE) and multiple working groups through which she has advised across UK government departments during the COVID-19 pandemic. Publisher Copyright: © 2022, The Author(s).

PY - 2022/3/23

Y1 - 2022/3/23

N2 - 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.

AB - 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.

KW - Air microbiology

KW - Antimicrobials

KW - Bacteria

KW - Civil engineering

KW - Influenza virus

KW - Lasers, LEDs and light sources

KW - Pathogens

KW - Public health

KW - Tuberculosis

KW - Viral infection

UR - https://www.scopus.com/pages/publications/85126834632

U2 - 10.1038/s41598-022-08462-z

DO - 10.1038/s41598-022-08462-z

M3 - Article

C2 - 35322064

SN - 2045-2322

VL - 12

JO - Scientific Reports

JF - Scientific Reports

M1 - 4373

ER -