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Rufyikiri AS, Martinez R, Addo PW, Wu BS, Yousefi M, Malo D, Orsat V, Vidal SM, Fritz JH, MacPherson S, Lefsrud M. Germicidal efficacy of continuous and pulsed ultraviolet-C radiation on pathogen models and SARS-CoV-2. Photochem Photobiol Sci 2024; 23:339-354. [PMID: 38308169 DOI: 10.1007/s43630-023-00521-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 12/12/2023] [Indexed: 02/04/2024]
Abstract
Ultraviolet radiation's germicidal efficacy depends on several parameters, including wavelength, radiant exposure, microbial physiology, biological matrices, and surfaces. In this work, several ultraviolet radiation sources (a low-pressure mercury lamp, a KrCl excimer, and four UV LEDs) emitting continuous or pulsed irradiation were compared. The greatest log reductions in E. coli cells and B. subtilis endospores were 4.1 ± 0.2 (18 mJ cm-2) and 4.5 ± 0.1 (42 mJ cm-2) with continuous 222 nm, respectively. The highest MS2 log reduction observed was 2.7 ± 0.1 (277 nm at 3809 mJ cm-2). Log reductions of SARS-CoV-2 with continuous 222 nm and 277 nm were ≥ 3.4 ± 0.7, with 13.3 mJ cm-2 and 60 mJ cm-2, respectively. There was no statistical difference between continuous and pulsed irradiation (0.83-16.7% [222 nm and 277 nm] or 0.83-20% [280 nm] duty rates) on E. coli inactivation. Pulsed 260 nm radiation (0.5% duty rate) at 260 nm yielded significantly greater log reduction for both bacteria than continuous 260 nm radiation. There was no statistical difference in SARS-CoV-2 inactivation between continuous and pulsed 222 nm UV-C radiation and pulsed 277 nm radiation demonstrated greater germicidal efficacy than continuous 277 nm radiation. Greater radiant exposure for all radiation sources was required to inactivate MS2 bacteriophage. Findings demonstrate that pulsed irradiation could be more useful than continuous UV radiation in human-occupied spaces, but threshold limit values should be respected. Pathogen-specific sensitivities, experimental setup, and quantification methods for determining germicidal efficacy remain important factors when optimizing ultraviolet radiation for surface decontamination or other applications.
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Affiliation(s)
- Anne Sophie Rufyikiri
- Department of Bioresource Engineering, Macdonald Campus, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Rebecca Martinez
- Department of Bioresource Engineering, Macdonald Campus, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Philip W Addo
- Department of Bioresource Engineering, Macdonald Campus, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Bo-Sen Wu
- Department of Bioresource Engineering, Macdonald Campus, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Mitra Yousefi
- Dahdaleh Institute of Genomic Medicine and McGill University Research Centre on Complex Traits, Life Sciences Complex, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Danielle Malo
- Dahdaleh Institute of Genomic Medicine and McGill University Research Centre on Complex Traits, Life Sciences Complex, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
- Department of Medicine, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
- Department of Human Genetics, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Valérie Orsat
- Department of Bioresource Engineering, Macdonald Campus, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Silvia M Vidal
- Dahdaleh Institute of Genomic Medicine and McGill University Research Centre on Complex Traits, Life Sciences Complex, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
- Department of Human Genetics, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
- Department of Microbiology and Immunology, McGill University, 3775 Rue University, Montreal, QC, H3A 2B4, Canada
| | - Jörg H Fritz
- Dahdaleh Institute of Genomic Medicine and McGill University Research Centre on Complex Traits, Life Sciences Complex, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
- Department of Microbiology and Immunology, McGill University, 3775 Rue University, Montreal, QC, H3A 2B4, Canada
| | - Sarah MacPherson
- Department of Bioresource Engineering, Macdonald Campus, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Mark Lefsrud
- Department of Bioresource Engineering, Macdonald Campus, McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada.
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Luo H, Zhang S, Zhong L. Ultraviolet germicidal irradiation: A prediction model to estimate UV-C-induced infectivity loss in single-strand RNA viruses. Environ Res 2024; 241:117704. [PMID: 37984783 DOI: 10.1016/j.envres.2023.117704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/22/2023]
Abstract
Ultraviolet germicidal irradiation (UVGI) disinfection technology is effective in inactivating microorganisms. However, its performance can vary against different microorganisms due to their diverse structural and genomic features. Thus, rapid predictions of UV (254 nm) inactivation kinetics are essential, particularly for highly infectious emerging pathogens, such as SARS-CoV-2, during the extemporary COVID-19 pandemic. In this study, aiming at single-strand RNA (ssRNA) viruses, an improved genomic model was introduced to predict the UV inactivation kinetics of viral genomes using genome sequence data. First, the overall virus infectivity loss in an aqueous matrix was estimated as the sum of damage to both the entire genome and the protein capsid. Then, the "UV rate constant ratio of aerosol and liquid" was used to convert the UV rate constant for viruses in a liquid-based matrix to an airborne state. The prediction model underwent both quantitative and qualitative validation using experimental data from this study and the literature. Finally, with the goal of mitigating potential airborne transmission of ssRNA viruses in indoor environments, this paper summarizes existing in-duct UVGI system designs and evaluates their germicidal performance. The prediction model may serve as a preliminary tool to assess the effectiveness of a UVGI system for emerging or unculturable viruses or to estimate the required UV dose when designing such a system.
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Affiliation(s)
- Hao Luo
- Department of Mechanical Engineering, University of Alberta, 9211-116 Street NW, Edmonton, Alberta, T6G 1H9, Canada
| | - Shuce Zhang
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Lexuan Zhong
- Department of Mechanical Engineering, University of Alberta, 9211-116 Street NW, Edmonton, Alberta, T6G 1H9, Canada.
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Ridder MP, Paladino KD, Lowe JJ, Rupp ME. A Practical Approach to Filtering Facepiece Respirator Decontamination and Reuse: Ultraviolet Germicidal Irradiation. Curr Treat Options Infect Dis 2021;:1-12. [PMID: 33841050 DOI: 10.1007/s40506-021-00247-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2021] [Indexed: 10/27/2022]
Abstract
Purpose of review Prior outbreaks of respiratory viruses have demonstrated the need for adequate personal protective equipment (PPE) for healthcare workers, particularly filtering facepiece respirators (FFR). Due to shortfalls of PPE during the SARS CoV-2 pandemic, the need for FFR decontamination and reuse (FFR-DR) strategies is paramount. This paper aims to discuss primary decontamination strategies, with an in-depth analysis of ultraviolet germicidal irradiation (UVGI), arriving at the decontamination strategy utilized at the Nebraska Medical Center (NMC). Methods Review of the primary literature in regard to FFR-DR as well as a synopsis of the current protocol for FFR-DR at NMC. Recent findings UVGI demonstrates effective decontamination of multiple pathogens-including several human respiratory viruses-while maintaining mask integrity and filtering capacity. UVGI was associated with degradation of strap integrity at higher doses than that utilized for decontamination or with reuse beyond 20 times. Summary UVGI effectively decontaminates N95 FFRs without significant reduction to fit or strap integrity and can be employed as a strategy for FFR-DR in times of emergency.
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Ou Q, Pei C, Chan Kim S, Abell E, Pui DYH. Evaluation of decontamination methods for commercial and alternative respirator and mask materials - view from filtration aspect. J Aerosol Sci 2020; 150:105609. [PMID: 32834104 PMCID: PMC7313496 DOI: 10.1016/j.jaerosci.2020.105609] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/03/2020] [Accepted: 06/04/2020] [Indexed: 05/20/2023]
Abstract
This study aims to evaluate the filtration performance of three commercially available (3M 8210 respirator, Halyard 48207 surgical mask, and 3M 1820 procedure mask) and two alternative face mask and respirator materials (Halyard H600 sterilization wrap and Cummins EX101) after selected decontamination treatments, including isopropanol (IPA) treatments (soaking or spraying), ultraviolet germicidal irradiation (UVGI), and heat treatments (dry heat at 77 °C or steam heat). Both IPA soaking and spraying removed most electrostatic charges on all four electret materials (three commercial and one alternative), causing significant deterioration of filtration efficiency to unacceptable level. The other non-electret alternative material sustained its N95-grade performance after both IPA soaking and spraying treatments, demonstrating the possible application of IPA disinfection for non-electret alternative respirator/mask materials. UVGI preserved the filtration of all three commercially available respirator/mask materials after up to 10 treatments, suggesting it can be a possible decontamination method for hospital and clinic use without compromising respirator/mask performance. The considerations of the practical implementation of this method was discussed. Between the two heat treatment methods tested, dry heat showed better compatibility with electret material by sustaining both filtration efficiency and fit (tested on commercial respirator only), although adding moisture was reported in favor of virus inactivation. Heat treatment is easily accessible method for general publics to implement at home, while it is recommended to maintain the moisture level below saturation. Comparing to size-integrated method, the size-resolved fractional efficiency measurement technique, although more time consuming, proved to be a better method for evaluating respirator/mask filtration performance after decontaminations by providing more sensitive detection of performance degradation and the capability of distinguishing charge loss to other mechanisms causing efficiency deterioration. Detailed descriptions are provided in methodology part to emphasize the cares needed for an appropriate efficiency evaluation. The limited results in this study on worn masks made of alternative sterilization wrap indicated possible performance degradation of electret material caused by normal human wearing activities, suggesting the need of assessing respirator/mask decontamination strategy by testing practically worn-and-decontaminated/reused samples instead of unworn only-decontaminated counterparts.
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Affiliation(s)
- Qisheng Ou
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Chenxing Pei
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Seong Chan Kim
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Elizabeth Abell
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - David Y H Pui
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
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Yang H, Hu J, Li P, Zhang C. Ultraviolet germicidal irradiation for filtering facepiece respirators disinfection to facilitate reuse during COVID-19 pandemic: A review. Photodiagnosis Photodyn Ther 2020; 31:101943. [PMID: 32763473 PMCID: PMC7402378 DOI: 10.1016/j.pdpdt.2020.101943] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 01/14/2023]
Abstract
UVGI is one possible method for respiratory disinfection to facilitate the reuse of dwindling supplies. Appropriate dose UVGI exposition could provide enough energy to effectively decontaminate respiratory viral agent and maintenance respirator's integrity for reuse. Further evidence concerning UVGI as a decontamination technique for SARS-COV-2 is needed.
Background To review the effect of ultraviolet germicidal irradiation (UVGI) as a disinfection method for filtering facepiece respirators (FFRs) to facilitate reuse during COVID-19 pandemic. Methods Systematic review of the research concerning UVGI for FFRs disinfection to facilitate reuse (also termed limited reuse) during respiratory infectious diseases where aerosol transmission is considered possible. Results UVGI is one possible method for respiratory disinfection to facilitate the reuse of dwindling supplies. Appropriate dose UVGI exposition could provide enough energy to effectively decontaminate respiratory viral agents and maintain respirator's integrity for reuse. There was not currently sufficient research evidence on the effect of UVGI to inactivate coronaviruses SARS-CoV-2, and the practical application of UVGI is still unclear. . Conclusion Appropriate dose UVGI exposition could provide enough energy to effectively decontaminate respiratory viral agents and maintain respirator's integrity for reuse. Further evidence concerning UVGI as a decontamination technique specifically for SARS-CoV-2 isneeded.
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Affiliation(s)
- Hua Yang
- Department of Thoracic Internal Medicine, Hunan Cancer Hospital, Affiliated Cancer Hospital of Xiangya Medical School, Central South University, Changsha, China
| | - Jiajia Hu
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, China
| | - Ping Li
- Department of Obstetrics, Xiangya Hospital, Central South University Changsha, China; Hunan Engineering Research Center of Early Life Development and Disease Prevention, Changsha,China
| | - Chengliang Zhang
- Department of Cardiovascular Surgery, Xiangya Hospital, Central South University, Changsha, China.
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Armellino D, Walsh TJ, Petraitis V, Kowalski W. Assessment of focused multivector ultraviolet disinfection withshadowless delivery using 5-point multisided sampling ofpatientcare equipment without manual-chemical disinfection. Am J Infect Control 2019; 47:409-14. [PMID: 30502110 DOI: 10.1016/j.ajic.2018.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND The aim of this study was to evaluate the performance of a focused multivector ultraviolet (FMUV) system employing shadowless delivery with a 90-second disinfection cycle for patient care equipment inside and outside the operating room (OR) suite without manual-chemical disinfection. METHODS A 5-point multisided sampling protocol was utilized to measure the microbial burden on objects inside and outside the OR environment in a 3-phase nonrandomized observational study. Surface sampling was performed pre- and postdisinfection in between cases (IBCs) to assess the performance of manual-chemical disinfection. FMUV system performance was separately assessed pre- and postdisinfection before the first case and IBCs. Additionally, visibly clean high-touch objects were sampled outside the OR, and the microbial burden reductions after FMUV disinfection were quantified without manual-chemical disinfection. RESULTS Manual-chemical disinfection reduced the active microbial burden on sampled objects IBCs by 52.8%-90.9% (P < .05). FMUV reduced the active microbial burden by 92%-97.7% (P < .0001) before the firstcase and IBCs combined, and 96.3%-99.6% (P < .0001) on objects outside the OR without chemical disinfection. CONCLUSIONS Five-point multisided sampling proved effective for assessing disinfection performance on all exterior sides of equipment. FMUV produced significant overall reductions of the microbial burden on patient care equipment in all study phases and independent of manual cleaning and chemical disinfection.
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Milonova S, Rudnick S, McDevitt J, Nardell E. Occupant UV exposure measurements for upper-room ultraviolet germicidal irradiation. J Photochem Photobiol B 2016; 159:88-92. [PMID: 27038734 DOI: 10.1016/j.jphotobiol.2016.03.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 03/04/2016] [Accepted: 03/07/2016] [Indexed: 11/24/2022]
Abstract
The threshold limit value (TLV) guideline for ultraviolet (UV) radiation specifies that irradiance measurements to ensure occupant safety be taken over an angle of 80° at the sensor. The purpose of this study was to evaluate the effect of an 80° field of view (FOV) tube on lower room UV-C irradiation measurements. Measurements were made in an experimental chamber at a height of 1.73m with and without an FOV tube. The FOV tube reduced the lower room irradiance readings by 18-34%, a statistically significant reduction compared to the bare sensor. An 80° FOV tube should be used for lower room irradiance measurements to comply with the TLV guideline. The resulting lower readings would allow more UV-C radiation in the upper room without compromising occupant safety. More UV-C radiation in the upper room could increase efficacy of UVGI systems for reducing transmission of airborne infectious diseases. In addition, recommendations are made to standardize lower room irradiance measurement techniques.
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Affiliation(s)
- Sonya Milonova
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
| | - Stephen Rudnick
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA
| | - James McDevitt
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA
| | - Edward Nardell
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA; Division of Global Health Equity, Brigham and Women's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
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Sung M, Kato S. Estimating the germicidal effect of upper-room UVGI system on exhaled air of patients based on ventilation efficiency. Build Environ 2011; 46:2326-2332. [PMID: 32288012 PMCID: PMC7127715 DOI: 10.1016/j.buildenv.2011.05.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/28/2011] [Accepted: 05/16/2011] [Indexed: 05/23/2023]
Abstract
Upper room (UR)-ultraviolet germicidal (UVGI) systems, one of several disinfection applications of UV, target airborne infectious diseases in rooms of buildings such as healthcare facilities. Previous studies have introduced many experiments showing the germicidal effect of UR-UVGI systems. In this study, a novel numerical method of estimating the germicidal effect of UR-UVGI systems for air exhaled by ward patients was introduced. The method adopts and modifies the concept of ventilation efficiency because the germicidal effect depends upon how the air containing airborne infectious particles flows and stays within UV-radiated area. A case study based on a four-patient ward showed that UV doses were correlated with the age of the air exhaled by a source patient, as expected. Moreover, the UV doses were considerably affected by the position of the UR-UVGI system. Inactivation rates of the influenza virus estimated using the UV doses, were in the range of 48-74%, and those of Mycobacterium tuberculosis were 68-90% in the breathing area of a neighboring patient. The results indicate not directly the decreased concentration of airborne infectious particles, but the possibility of inactivation caused by the UR-UVGI system, which is useful for system optimization.
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Affiliation(s)
- Minki Sung
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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