Interim indications for the use of UV germicidal irradiation in the conjuncture of COVID-19 pandemic
The ultraviolet radiation in the range 100 -280 nm (UV-C) has a well-known germicidal efficiency due to the disruptive mechanism on the nucleic acids, RNA and DNA, of microorganisms. The UV-C based disinfecting technology is commonly used, for example, in biosafety cabinets in hospitals and laboratories. Although the UV-C would be useful for its germicidal action, caution must be used when the UV-C use could imply human exposure. The phototoxicity of the UV-C radiation can induce damage to most external organs, eyes and skin and exposure limits for acute effects must be respected in order to protect the human health and safety. In addition, the UV-C radiation is known to have stochastic effects and for this reason has been classified by the IARC (International Agency for Research on Cancer) as a class I carcinogenic agent. The COVID-19 pandemic outbreak raised the question of disinfecting living and working environments especially when they are shared by many people, this issue being particularly urgent in hospitals where the viral concentration due to patients affected by Covid-19 can be very high. Although the hospitals are the environments that most need disinfection, also transport means, markets, schools, commercial centers have to be disinfected in order to control the spreading of the infection. The effectiveness of the UV-C against microorganisms aroused a great interest during the pandemic outbreak, and several new devices for disinfection based on this technology have been proposed in the market with different use. Although there is lack of studies determining precisely the lethal UV-C dose in the case of COVID-19, many studies have been carried out in the recent past regarding the UV-C inactivation efficiency against very similar microorganisms, such as those causing the SARS and the MERS belonging to the same family Coronaviridae. The effectiveness of UV-C radiation in killing microorganisms, including respiratory viruses that were found relatively highly susceptible, is well assessed, but caution must be used when the use of UV-C based technology implies human exposure. The right compromise between effective disinfection objective and human health protection must be found, quantitatively evaluating each specific situation. The limit of human exposure must be respected and an accurate cost/benefit ratio must be evaluated in the case of doses well below the exposure limits for acute effects. In this work, the concepts of lethal dose in terms of irradiance and exposure time are discussed in the light of the human exposure limits with respect to different UV-C radiation practical applications.
Examples are drawn by the literature and by the direct experience of the authors.
This work is addressed, in particular, to health physicists and biomedical engineers. Technical personnel with adequate expertise could use these indications for developing and maybe sharing specific experiences. Further research is recommended at the aim of improving the disinfection techniques based on optical radiation. Beyond the epidemic conjuncture, this work could be useful also in fighting the increasing spread of multiresistant bacteria in hospitals reducing healthcare personnel exposure to complex mixtures of disinfectants
ASHRAE, 2019. Handbook 62.2 —HVAC Applications Ultraviolet Air and Surface Treatment, 2.
ASHRAE, 2020. Position Document on Infectious Aerosols. approved on April 14 2020 expires on April 14, 2023.
ASTM, 2018. ASTM D1148 – 13. Standard Test Method for Rubber Deterioration—Discoloration from Ultraviolet (UV) or UV/Visible Radiation and Heat Exposure of Light-Colored Surfaces.
Beck et al., 2014. Action spectra for validation of pathogen disinfection in medium-pressure ultraviolet (UV) systems. Water Research, Elseviere. https://doi.org/10.1016/j.watres.2014.11.028
Bergman, M., et al., 2010. Evaluation of Multiple (3-Cycle) Decontamination Processing for Filtering Facepiece Respirators. Journal of Engineered Fibers and Fabrics, 5 (4), 33 - 41.
Bergman, M., et al., 2011. Impact of Three Cycles of Decontamination Treatments on Filtering Facepiece Respirator Fit. Journal of the International Society for Respiratory Protection, 28 (1), 48 - 59.
Bowker et al., 2011. Microbial UV fluence-response assessment using a novel UV-LED collimated beam system. Water Research, Elseviere. https://doi.org/10.1016/j.watres.2010.12.005
Chetan et al., 2015. Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection? American Journal of Infection Control, 43, 415 – 417. https://www.ajicjournal.org/article/S0196-6553(14)01398-4/fulltext
CIE, 2003. COMMISSION INTERNATIONALE DE L'ECLAIRAGE Technical Report CIE 155:2003 Ultraviolet Air Disinfection. ISBN 978 3 901906 25 1
Factor, A., 1996. Mechanisms of thermal and photodegradation of bisphenol A polycarbonate. In Advanced Chemistry Series (Polymer Durability), 59 - 76.
Handke, D.C., 2019. Examining the Effects of UV on Latex and Nitrile Glove Degradation. An undergraduate thesis presented to the Faculty of The Environmental Studies Program at the University of Nebraska – Lincoln.
Health Quality Ontario, 2018. Portable ultraviolet light surface-disinfecting devices for prevention of hospital-acquired infections: a health technology assessment. Ont. Health Technol. Assess. Ser., 18 (1), 1 - 73. Available from: http://www.hqontario.ca/evidence-to-improve-care/journal-ontario-health-technology-assessment-series
Heimbuch, B.K., et al., 2011. A pandemic influenza preparedness study: use of energetic methods to decontaminate filtering facepiece respirators contaminated with H1N1 aerosols and droplets. American Journal of Infection Control, 39 (1), e1 - e9.
Heimbuch, B.K., Harnish, D., 2019. Research to Mitigate a Shortage of Respiratory Protection Devices During Public Health Emergencies. (https://www.ara.com/news/ara-research-mitigate-shortage-respiratory-protection-devices-during-public-health-emergencies).
ICNIRP, 2004. Guidelines on limits of exposure to ultraviolet radiation of wavelengths between 180 nm and 400 nm (incoherent optical radiation). Health Physics, Vol. 87, n° 2.
ISO, 2016. ISO 4892-3:2016. Plastics — Methods of exposure to laboratory light sources — Part 3: Fluorescent UV lamps.
ISS, 2020 a. Rapporto ISS COVID-19 n. 25/2020. Raccomandazioni ad interim sulla sanificazione di strutture non sanitarie nell’attuale emergenza COVID-19: superfici, ambienti interni e abbigliamento. Versione del 15 maggio 2020.
ISS, 2020 b. Rapporto ISS COVID-19 n. 5/2020 Rev. 2 - Indicazioni ad interim per la prevenzione e gestione degli ambienti indoor in relazione alla trasmissione dell’infezione da virus SARS-CoV-2. Versione del 25 maggio 2020.
Kowalski et al., 2020. COVID-19 Coronavirus Ultraviolet Susceptibility. https://www.researchgate.net/publication/284691618_SARS_Coronavirus_UV_Susceptibility
Lambert, S., Sinclair, C.J., Bradley, E.L., Boxall, A.B.A., 2013.Effects of environmental conditions on latex degradation in aquatic systems Science of The Total Environment Vol. 447, 225 - 234.
Lindsley, W.G., et al., 2015. Effects of ultraviolet germicidal irradiation (UVGI) on N95 respirator filtration performance and structural integrity. Journal of Occupational and Environmental Hygiene, 12 (8), 509 - 517.
Meechan, P.J and Wilson, C., 2006. Use of Ultraviolet Lights in Biological Safety Cabinets: A Contrarian View. Applied Biosafety, 11 (4), 222 - 227. https://doi.org/10.1177%2F153567600601100412
Mills D., et al., 2018. Ultraviolet germicidal irradiation of influenza-contaminated N95 filtering facepiece respirators. American Journal of Infection Control, 46 (7), e49 - e55.
Noriman, N., Ismail, H., 2010. Natural Weathering test of styrene butadiene rubber and recycled acronitrile butadiene rubber blends. Polymer Plastics-Technology and Engineering.
Perincek, S., Duran, K., Körlü, A.E., Elemen, S., Can, C., 2014. Disinfection of cellulosic material contaminated with S. Aureus and K. Pneumoniae. XIIIth International Izmir Textile and Apparel Symposium.
Pinto, I., Bogi, A., Stacchini, N., 2015. Procedure operative per la prevenzione del rischio da esposizione a Radiazioni Ottiche Artificiali: Cappe sterili e Lampade Germicide https://www.portaleagentifisici.it/filemanager/userfiles/DOCUMENTAZIONE/ROA_DOCUMENTAZIONE/report_paf_roa_2_04_2015_UVC.pdf?lg=IT
Rivaton, A., et al., 1986. The photo-chemistry of bisphenol-A polycarbonate reconsidered: Part 3 – Influence of water on polycarbonate photochemistry. Polymer Degradation and Stability, Vol. 14, 23 - 40.
Szeto, W., Yam, W.C., Huang, H., Leung, D.Y.C, 2020. The Efficacy of Vacuum-Ultraviolet Light Disinfection of Some Common Environmental Pathogens. BMC Infect Dis., 20 (1), 127. doi: 10.1186/s12879-020-4847-9
Tjandraatmadja, G.F., Burn, L.S., Jollands, M.J., 1999. The effects of ultraviolet radiation on polycarbonate glazing in Durability of Building Materials and Components 8: Service life and durability of materials and components. Michael A. Lacasse, Dana J. Vanier. NRC Research Press.
Veitch, J.A., McColl, S.L., 1995. Modulation of fluorescent light: Flicker rate and light source effects on visual performance and visual comfort. Lighting Research and Technology, 27, 243 - 256.
Viscusi, D.J., et al., 2009. Evaluation of five decontamination methods for filtering facepiece respirators. Annals of occupational hygiene, 53 (8), 815 - 827.
Viscusi, D.J., et al., 2011. Impact of three biological decontamination methods on filtering facepiece respirator fit, odor, comfort, and donning ease. Journal of Occupational and Environmental Hygiene, 8 (7), 426 - 436.
Viscusi, D.J., King, W.P., Shafer, R.E., 2007. Effect of decontamination on the filtration efficiency of two filtering facepiece respirator models. Journal of the International Society for Respiratory Protection, 24, 93 - 107.
Vo, E., Rengasamy, S., Shaffer, R., 2009. Development of a Test System to Evaluate Procedures for Decontamination of Respirators Containing Viral Droplets. Applied and Environmental Microbiology, 75 (23), 7303 - 7309.
Wang, C., Lu, S., Zhang, Z., 2019. Inactivation of Airborne Bacteria Using Different UV Sources: Performance Modeling, Energy Utilization, and Endotoxin Degradation. Sci. Total Environ.; 655, 787 - 795. doi: 10.1016/j.scitotenv.2018.11.266
Welch et al., 2017. Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases. Scientific Reports. https://www.nature.com/articles/s41598-018-21058-w#citeas
WHO, 2020. Rational use of personal protective equipment for coronavirus disease (COVID-19) and considerations during severe shortages Interim guidance 6 April 2020 WHO/2019-nCov/IPC_PPE_use/2020.3
Yousif, E., Haddad, R., 2013. Photodegradation and photostabilization of polymers, especially polystyrene: review. SpringerPlus, 2, 398.
Zaffina S., et al., 2012. Accidental Exposure to UV Radiation Produced by Germicidal Lamp: Case Report and Risk Assessment Photochemistry and Photobiology, 88, 1001 - 1004. doi: 10.1111/j.1751-1097.2012.01151.x