Assessing the safety of new germicidal far-UVC technologies

Maximilian Görlitz; Lennart Justen; Patrick J Rochette; Manuela Buonanno; David Welch; Norman J Kleiman; Ewan Eadie; Sachiko Kaidzu; William J Bradshaw; Emilia Javorsky; Nigel Cridland; Anat Galor; Martin Guttmann; Martina C Meinke; Johannes Schleusener; Paul Jensen; Per Söderberg; Nozomi Yamano; Chikako Nishigori; Paul O'Mahoney; Dieter Manstein; Rodney Croft; Curtis Cole; Frank R de Gruijl; Paul Donald Forbes; Stephen Trokel; John Marshall; David J Brenner; David Sliney; Kevin Esvelt

doi:10.1111/php.13866

Assessing the safety of new germicidal far-UVC technologies

Photochem Photobiol. 2023 Nov 6. doi: 10.1111/php.13866. Online ahead of print.

Authors

Maximilian Görlitz^{1

2}, Lennart Justen^{1

2}, Patrick J Rochette³, Manuela Buonanno⁴, David Welch⁴, Norman J Kleiman⁵, Ewan Eadie⁶, Sachiko Kaidzu⁷, William J Bradshaw^{1

2}, Emilia Javorsky^{8

9}, Nigel Cridland¹⁰, Anat Galor¹¹, Martin Guttmann¹², Martina C Meinke¹³, Johannes Schleusener¹³, Paul Jensen¹⁴, Per Söderberg¹⁵, Nozomi Yamano¹⁶, Chikako Nishigori^{16

17}, Paul O'Mahoney¹⁸, Dieter Manstein¹⁹, Rodney Croft^{20

21}, Curtis Cole²², Frank R de Gruijl²³, Paul Donald Forbes²⁴, Stephen Trokel²⁵, John Marshall²⁶, David J Brenner⁴, David Sliney^{27

28}, Kevin Esvelt^{1

2}

Affiliations

¹ Massachusetts Institute of Technology, Media Lab, Cambridge, Massachusetts, USA.
² SecureBio, Inc., Cambridge, Massachusetts, USA.
³ Centre de recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice Quebec, Quebec City, Quebec, Canada.
⁴ Center for Radiological Research, Columbia University Medical Center, New York City, New York, USA.
⁵ Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York City, New York, USA.
⁶ Photobiology Unit, Ninewells Hospital, Dundee, UK.
⁷ Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo, Japan.
⁸ Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, USA.
⁹ Future of Life Institute, Cambridge, Massachusetts, USA.
¹⁰ Radiation, Chemicals and Environment Directorate, UK Health Security Agency, Didcot, UK.
¹¹ Miami Veterans Affairs Medical Center, University of Miami Health System Bascom Palmer Eye Institute, Miami, Florida, USA.
¹² Ferdinand-Braun-Institut gGmbH, Berlin, Germany.
¹³ Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
¹⁴ Final Approach Inc., Port Orange, Florida, USA.
¹⁵ Ophthalmology, Department of Surgical Sciences, Uppsala Universitet, Uppsala, Sweden.
¹⁶ Division of Dermatology, Department of Internal Related, Kobe University, Kobe, Japan.
¹⁷ Japanese Red Cross Hyogo Blood Center, Kobe, Japan.
¹⁸ Optical Radiation Effects, UK Health Security Agency, Chilton, UK.
¹⁹ Department of Dermatology, Cutaneous Biology Research Center, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA.
²⁰ International Commission on Non-Ionizing Radiation Protection (ICNIRP), Chair, Wollongong, New South Wales, Australia.
²¹ University of Wollongong, Wollongong, New South Wales, Australia.
²² Sun & Skin Consulting LLC, New Holland, Pennsylvania, USA.
²³ Department of Dermatology, Universiteit Leiden, Leiden, South Holland, The Netherlands.
²⁴ Toxarus, Inc., Malvern, Pennsylvania, USA.
²⁵ Department of Ophthalmology, Columbia University Vagelos College of Physicians and Surgeons, New York City, New York, USA.
²⁶ Institute of Ophthalmology, University College London, London, UK.
²⁷ IES Photobiology Committee, Chair, Fallston, Maryland, USA.
²⁸ Consulting Medical Physicist, Fallston, Maryland, USA.

PMID: 37929787
DOI: 10.1111/php.13866

Abstract

The COVID-19 pandemic underscored the crucial importance of enhanced indoor air quality control measures to mitigate the spread of respiratory pathogens. Far-UVC is a type of germicidal ultraviolet technology, with wavelengths between 200 and 235 nm, that has emerged as a highly promising approach for indoor air disinfection. Due to its enhanced safety compared to conventional 254 nm upper-room germicidal systems, far-UVC allows for whole-room direct exposure of occupied spaces, potentially offering greater efficacy, since the total room air is constantly treated. While current evidence supports using far-UVC systems within existing guidelines, understanding the upper safety limit is critical to maximizing its effectiveness, particularly for the acute phase of a pandemic or epidemic when greater protection may be needed. This review article summarizes the substantial present knowledge on far-UVC safety regarding skin and eye exposure and highlights research priorities to discern the maximum exposure levels that avoid adverse effects. We advocate for comprehensive safety studies that explore potential mechanisms of harm, generate action spectra for crucial biological effects and conduct high-dose, long-term exposure trials. Such rigorous scientific investigation will be key to determining safe and effective levels for far-UVC deployment in indoor environments, contributing significantly to future pandemic preparedness and response.

Keywords: 222 nm; COVID-19; biosecurity; far-UVC; germicidal ultraviolet; indoor air quality; pandemic preparedness; ultraviolet.

Publication types

Review