1
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Yang T, Zeng G, Jiang M, Su P, Liu C, Lv Q, Li W, Hou X, Li J. Matching periodate peak absorbance by far UVC at 222 nm promotes the degradation of micropollutants and energy efficiency. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134978. [PMID: 38905986 DOI: 10.1016/j.jhazmat.2024.134978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/09/2024] [Accepted: 06/18/2024] [Indexed: 06/23/2024]
Abstract
Periodate (PI)-based advanced oxidation processes have gained increasing interest. This study for the first time elevates the light-activation capacity of PI by using far UVC at 222 nm (UV222/PI) without extra chemical inputs. The effectiveness and the underlying mechanisms of UV222/PI for the remediation of micropollutants were studied by selecting atenolol (ATL) as a representative. PI possessed a high molar absorption coefficient of 9480-6120 M-1 cm-1 at 222 nm in the pH range of 5.0-9.0, and it was rapidly decomposed by UV222 with first-order rate constants of 0.0055 to 0.002 s-1. ATL and the six other organic compounds were effectively degraded by the UV222/PI process under different conditions with the fluence-based rate constants generally two to hundred times higher than by UVA photolysis. Hydroxyl radical and ozone were confirmed as the major contributors to ATL degradation, while direct photolysis also played a role at higher pH or lower PI dosages. Degradation pathways of ATL were proposed including hydroxylation, demethylation, and oxidation. The high energy efficiency of the UV222/PI process was also confirmed. This study provides a cost-effective and convenient approach to enhance PI light-response activity for the treatment of micropollutants.
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Affiliation(s)
- Tao Yang
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China; Institute of Carbon Peaking and Carbon Neutralization, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Ge Zeng
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Maoju Jiang
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Peng Su
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Chenlong Liu
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Qixiao Lv
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Wenqi Li
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Xiangyang Hou
- Jiangmen Key Laboratory of Synthetic Chemistry and Cleaner Production, School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, Guangdong Province, China
| | - Juan Li
- Advanced Interdisciplinary Institute of Environment and Ecology, Guangdong Provincial Key Laboratory of Wastewater Information Analysis and Early Warning, Beijing Normal University, Zhuhai 519087, China.
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2
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Pangerl J, Sukul P, Rück T, Fuchs P, Weigl S, Miekisch W, Bierl R, Matysik FM. An inexpensive UV-LED photoacoustic based real-time sensor-system detecting exhaled trace-acetone. PHOTOACOUSTICS 2024; 38:100604. [PMID: 38559568 PMCID: PMC10973644 DOI: 10.1016/j.pacs.2024.100604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/08/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024]
Abstract
In this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) - providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 8.3 ppbV and an NNEA of 1.4E-9 Wcm-1Hz-0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field.
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Affiliation(s)
- Jonas Pangerl
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
- Institute of Analytical Chemistry, Chemo- and Biosensing, University of Regensburg, Regensburg 93053, Germany
| | - Pritam Sukul
- Rostock Medical Breath Analytics and Technologies (RoMBAT), Dept. of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Medicine Rostock, Rostock 18057, Germany
| | - Thomas Rück
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
| | - Patricia Fuchs
- Rostock Medical Breath Analytics and Technologies (RoMBAT), Dept. of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Medicine Rostock, Rostock 18057, Germany
| | - Stefan Weigl
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
| | - Wolfram Miekisch
- Rostock Medical Breath Analytics and Technologies (RoMBAT), Dept. of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Medicine Rostock, Rostock 18057, Germany
| | - Rudolf Bierl
- Sensorik-ApplikationsZentrum (SappZ), Regensburg University of Applied Sciences, Regensburg 93053, Germany
| | - Frank-Michael Matysik
- Institute of Analytical Chemistry, Chemo- and Biosensing, University of Regensburg, Regensburg 93053, Germany
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3
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Jenks O, Peng Z, Schueneman MK, Rutherford M, Handschy AV, Day DA, Jimenez JL, de Gouw JA. Effects of 222 nm Germicidal Ultraviolet Light on Aerosol and VOC Formation from Limonene. ACS ES&T AIR 2024; 1:725-733. [PMID: 39021671 PMCID: PMC11249781 DOI: 10.1021/acsestair.4c00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 07/20/2024]
Abstract
Since the 1930s, germicidal ultraviolet (GUV) irradiation has been used indoors to prevent the transmission of airborne diseases, such as tuberculosis and measles. Recently, it has received renewed attention due to the COVID-19 pandemic. While GUV radiation has been shown to be effective in inactivating airborne bacteria and viruses, few studies on the impact of GUV on indoor air quality have been published. In this work, we evaluate the effects of GUV222 (GUV at 222 nm) on the chemistry of a common indoor volatile organic compound (VOC), limonene. We found that the production of O3 by the GUV222 lamps caused the formation of particulate matter (PM) and oxygenated volatile organic compounds (VOCs). We also found that the chemistry proceeds through the ozonolysis of limonene as well as the reaction with secondary OH, and that the presence of GUV light led to observable but small perturbations to this chemistry. Understanding the effects of GUV222 on indoor air quality is important in evaluating the safety of these devices.
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Affiliation(s)
- Olivia
J. Jenks
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
| | - Zhe Peng
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
| | - Melinda K. Schueneman
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
| | - Madison Rutherford
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
| | - Anne V. Handschy
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
| | - Douglas A. Day
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
| | - Jose L. Jimenez
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
| | - Joost A. de Gouw
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative
Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado 80309, United States
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4
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van der Schans M, Yu J, de Vries A, Martin G. Estimation of the UV susceptibility of aerosolized SARS-CoV-2 to 254 nm irradiation using CFD-based room disinfection simulations. Sci Rep 2024; 14:15963. [PMID: 38987323 PMCID: PMC11237116 DOI: 10.1038/s41598-024-63472-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 05/28/2024] [Indexed: 07/12/2024] Open
Abstract
The recent COVID-19 pandemic has raised interest in efficient air disinfection solutions. The application of germicidal ultraviolet (GUV) irradiation is an excellent contender to prevent airborne transmission of COVID-19, as well as other existing and future infectious airborne diseases. While GUV has already been proven effective in inactivating SARS-CoV-2, quantitative data on UV susceptibility and dose requirements, needed to predict and optimize the performance of GUV solutions, is still limited. In this study, the UV susceptibility of aerosolized SARS-CoV-2 to 254 nm ultraviolet (UV) irradiation is investigated. This is done by employing 3D computational fluid dynamics based simulations of SARS-CoV-2 inactivation in a test chamber equipped with an upper-room UV-C luminaire and comparing the results to previously published measurements performed in the same test chamber. The UV susceptibility found in this study is (0.6 ± 0.2) m2/J, which is equivalent to a D90 dose between 3 and 6 J/m2. These values are in the same range as previous estimations based on other corona viruses and inactivation data reported in literature.
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Affiliation(s)
| | - Joan Yu
- Signify, High Tech Campus 7, 5656AE, Eindhoven, The Netherlands
| | - Adrie de Vries
- Signify, High Tech Campus 7, 5656AE, Eindhoven, The Netherlands
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5
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Markovitsi D. On the Use of the Intrinsic DNA Fluorescence for Monitoring Its Damage: A Contribution from Fundamental Studies. ACS OMEGA 2024; 9:26826-26837. [PMID: 38947837 PMCID: PMC11209687 DOI: 10.1021/acsomega.4c02256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/02/2024] [Accepted: 05/08/2024] [Indexed: 07/02/2024]
Abstract
The assessment of DNA damage by means of appropriate fluorescent probes is widely spread. In the specific case of UV-induced damage, it has been suggested to use the emission of dimeric photoproducts as an internal indicator for the efficacy of spermicidal lamps. However, in the light of fundamental studies on the UV-induced processes, outlined in this review, this is not straightforward. It is by now well established that, in addition to photodimers formed via an electronic excited state, photoionization also takes place with comparable or higher quantum yields, depending on the irradiation wavelength. Among the multitude of final lesions, some have been fully characterized, but others remain unknown; some of them may emit, while others go undetected upon monitoring fluorescence, the result being strongly dependent on both the irradiation and the excitation wavelength. In contrast, the fluorescence of undamaged nucleobases associated with emission from ππ* states, localized or excitonic, appearing at wavelengths shorter than 330 nm is worthy of being explored to this end. Despite its low quantum yield, it is readily detected nowadays. Its intensity decreases due to the disappearance of the reacting nucleobases and the loss of exciton coherence provoked by the presence of lesions, independently of their type. Thus, it could potentially provide valuable information about the DNA damage induced, not only by UV radiation but also by other sanitizing or therapeutic agents.
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Affiliation(s)
- Dimitra Markovitsi
- Université Paris-Saclay, CNRS,
Institut de Chimie Physique, UMR8000, 91405 Orsay, France
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6
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Zhu Q, Li F, Han Q, Zhang S. Two-dimensional Keitz method for the radiant power measurement of planar ultraviolet excilamps. APPLIED OPTICS 2024; 63:4131-4143. [PMID: 38856507 DOI: 10.1364/ao.520397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/26/2024] [Indexed: 06/11/2024]
Abstract
Planar X e B r ∗ and X e C l ∗ excilamps emitting noncoherent narrowband UVB light (280-315 nm) are now widely used to cure psoriasis and vitiligo as well as to improve vitamin D synthesis. The two-dimensional integral formula has been deducted in this study, which is a good method and has great practical significance to calculate the total radiant power and assess the energy efficiency of a planar UV lamp. The measured radiant power of planar white LED lamps through a two-dimensional Keitz formula has been compared to that of gonio-photometer, verifying the applicability of the formula. The optimum measurement distance is dependent on the lamp length (1.5L≤D≤3.5L) for which the derivation from the two methods can be controlled within 10%. The planar X e B r ∗ excilamps have been measured and compared to coaxial excilamps, which show similar patterns of change for the radiant characteristics. Since the planar radiant power formula only needs to measure normal illuminance at a certain distance from the symmetric center of the lamp, it is more convenient to use and is a low-cost method to promote the development of large-sized planar ultraviolet lamps.
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7
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Monika, Madugula SK, Kondabagil K, Kunwar A. Far-UVC (222 nm) irradiation effectively inactivates ssRNA, dsRNA, ssDNA, and dsDNA viruses as compared to germicidal UVC (254 nm). Photochem Photobiol 2024. [PMID: 38736273 DOI: 10.1111/php.13961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/14/2024]
Abstract
Ultraviolet-C (UVC) irradiation is being used as an effective approach for the disinfection of pathogenic viruses present in air, surfaces, and water. Recently, far-UVC radiation (222 nm) emitted by KrCl* (krypton-chloride) excimer lamps have been recommended for disinfecting high-risk public spaces to reduce the presence and transmission of infectious viruses owing to limited human health exposure risks as compared to germicidal UVC (254 nm). In this study, the UVC inactivation performances of individual filtered KrCl* excimer lamp (222 nm) and germicidal UVC lamp (254 nm) were determined against four viruses, bacteriophages MS2, Phi6, M13, and T4, having different genome compositions (ssRNA, dsRNA, ssDNA and dsDNA, respectively) and shapes (i.e., spherical (Phi6), linear (M13), and icosahedral (MS2 and T4)). Here, the disinfection efficacies of filtered KrCl* excimer lamp (222 nm) and germicidal UVC lamp (254 nm) were evaluated for highly concentrated virus droplets that mimic the virus-laden droplets released from the infected person and deposited on surfaces as fomites. Filtered KrCl* excimer (222 nm) showed significantly better inactivation against all viruses having different genome compositions and structures compared to germicidal UVC (254 nm). The obtained sensitivity against the filtered KrCl* excimer (222 nm) was found to be in the order, T4 > M13 > Phi6 > MS2 whereas for the germicidal UVC (254 nm) it was T4 > M13 > MS2 > Phi6. These results provide a strong basis to promote the use of filtered KrCl* excimer lamps (222 nm) in disinfecting contagious viruses and to limit the associated disease spread in public places and other high-risk areas.
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Affiliation(s)
- Monika
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Santhosh Kumar Madugula
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Kiran Kondabagil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Ambarish Kunwar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
- Koita Centre for Digital Health (KCDH), Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
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8
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Görlitz M, Justen L, Rochette PJ, Buonanno M, Welch D, Kleiman NJ, Eadie E, Kaidzu S, Bradshaw WJ, Javorsky E, Cridland N, Galor A, Guttmann M, Meinke MC, Schleusener J, Jensen P, Söderberg P, Yamano N, Nishigori C, O'Mahoney P, Manstein D, Croft R, Cole C, de Gruijl FR, Forbes PD, Trokel S, Marshall J, Brenner DJ, Sliney D, Esvelt K. Assessing the safety of new germicidal far-UVC technologies. Photochem Photobiol 2024; 100:501-520. [PMID: 37929787 DOI: 10.1111/php.13866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 11/07/2023]
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.
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Affiliation(s)
- Maximilian Görlitz
- Massachusetts Institute of Technology, Media Lab, Cambridge, Massachusetts, USA
- SecureBio, Inc., Cambridge, Massachusetts, USA
| | - Lennart Justen
- Massachusetts Institute of Technology, Media Lab, Cambridge, Massachusetts, USA
- SecureBio, Inc., Cambridge, Massachusetts, USA
| | - Patrick J Rochette
- Centre de recherche du CHU de Québec-Université Laval, Axe Médecine Régénératrice Quebec, Quebec City, Quebec, Canada
| | - Manuela Buonanno
- Center for Radiological Research, Columbia University Medical Center, New York City, New York, USA
| | - David Welch
- Center for Radiological Research, Columbia University Medical Center, New York City, New York, USA
| | - Norman J Kleiman
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York City, New York, USA
| | - Ewan Eadie
- Photobiology Unit, Ninewells Hospital, Dundee, UK
| | - Sachiko Kaidzu
- Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo, Japan
| | - William J Bradshaw
- Massachusetts Institute of Technology, Media Lab, Cambridge, Massachusetts, USA
- SecureBio, Inc., Cambridge, Massachusetts, USA
| | - Emilia Javorsky
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, USA
- Future of Life Institute, Cambridge, Massachusetts, USA
| | - Nigel Cridland
- Radiation, Chemicals and Environment Directorate, UK Health Security Agency, Didcot, UK
| | - Anat Galor
- Miami Veterans Affairs Medical Center, University of Miami Health System Bascom Palmer Eye Institute, Miami, Florida, USA
| | | | - Martina C Meinke
- Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Johannes Schleusener
- Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Paul Jensen
- Final Approach Inc., Port Orange, Florida, USA
| | - Per Söderberg
- Ophthalmology, Department of Surgical Sciences, Uppsala Universitet, Uppsala, Sweden
| | - Nozomi Yamano
- Division of Dermatology, Department of Internal Related, Kobe University, Kobe, Japan
| | - Chikako Nishigori
- Division of Dermatology, Department of Internal Related, Kobe University, Kobe, Japan
- Japanese Red Cross Hyogo Blood Center, Kobe, Japan
| | - Paul O'Mahoney
- Optical Radiation Effects, UK Health Security Agency, Chilton, UK
| | - Dieter Manstein
- Department of Dermatology, Cutaneous Biology Research Center, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Rodney Croft
- International Commission on Non-Ionizing Radiation Protection (ICNIRP), Chair, Wollongong, New South Wales, Australia
- University of Wollongong, Wollongong, New South Wales, Australia
| | - Curtis Cole
- Sun & Skin Consulting LLC, New Holland, Pennsylvania, USA
| | - Frank R de Gruijl
- Department of Dermatology, Universiteit Leiden, Leiden, South Holland, The Netherlands
| | | | - Stephen Trokel
- Department of Ophthalmology, Columbia University Vagelos College of Physicians and Surgeons, New York City, New York, USA
| | - John Marshall
- Institute of Ophthalmology, University College London, London, UK
| | - David J Brenner
- Center for Radiological Research, Columbia University Medical Center, New York City, New York, USA
| | - David Sliney
- IES Photobiology Committee, Chair, Fallston, Maryland, USA
- Consulting Medical Physicist, Fallston, Maryland, USA
| | - Kevin Esvelt
- Massachusetts Institute of Technology, Media Lab, Cambridge, Massachusetts, USA
- SecureBio, Inc., Cambridge, Massachusetts, USA
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9
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Lu YH, Wang RX, Liu HL, Lai ACK. Evaluating the Performance of UV Disinfection across the 222-365 nm Spectrum against Aerosolized Bacteria and Viruses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6868-6877. [PMID: 38593035 DOI: 10.1021/acs.est.3c08675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Bioaerosols play a significant role in the transmission of many infectious diseases, especially in enclosed indoor environments. Ultraviolet (UV) disinfection has demonstrated a high efficacy in inactivating microorganisms suspended in the air. To develop more effective and efficient UV disinfection protocols, it is necessary to evaluate and optimize the effectiveness of UV disinfection against aerosolized bacteria and viruses across the entire UV spectrum. In this study, we evaluated the performance of UV disinfection across the UV spectrum, ranging from 222 to 365 nm, against aerosolized bacteria and viruses, including Escherichia coli, Staphylococcus epidermidis, Salmonella enterica, MS2, P22, and Phi6. Six commonly available UV sources, including gas discharge tubes and light-emitting diodes with different emission spectra, were utilized, and their performance in terms of inactivation efficacy, action spectrum, and energy efficiency was determined. Among these UV sources, the krypton chloride excilamp emitting at a peak wavelength of 222 nm was the most efficient in inactivating viral bioaerosols. A low-pressure mercury lamp emitting at 254 nm performed well on both inactivation efficacy and energy efficiency. A UV light-emitting diode emitting at 268 nm demonstrated the highest bacterial inactivation efficacy, but required approximately 10 times more energy to achieve an equivalent inactivation level compared with that of the krypton chloride excilamp and low-pressure mercury lamp. This study provides insights into UV inactivation on bioaerosols, which can guide the development of effective wavelength-targeted UV air disinfection technologies and may significantly help reduce bioaerosol transmission in public areas.
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Affiliation(s)
- Y H Lu
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - R X Wang
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - H L Liu
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - A C K Lai
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
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10
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Stanton EJ, Tønning P, Ulsig EZ, Calmar S, Stanton MA, Thomsen ST, Gravesen KB, Johansen P, Volet N. Continuous-wave second-harmonic generation in the far-UVC pumped by a blue laser diode. Sci Rep 2024; 14:3238. [PMID: 38331948 PMCID: PMC10853522 DOI: 10.1038/s41598-024-53144-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/29/2024] [Indexed: 02/10/2024] Open
Abstract
Far-UVC light in the wavelength range of 200-230 nm has attracted renewed interest because of its safety for human exposure and effectiveness in inactivating pathogens. Here we present a compact solid-state far-UVC laser source based on second-harmonic generation (SHG) using a low-cost commercially-available blue laser diode pump. Leveraging the high intensity of light in a nanophotonic waveguide and heterogeneous integration, our approach achieves Cherenkov phase-matching across a bonded interface consisting of a silicon nitride (SiN) waveguide and a beta barium borate (BBO) nonlinear crystal. Through systematic investigations of waveguide dimensions and pump power, we analyze the dependencies of Cherenkov emission angle, conversion efficiency, and output power. Experimental results confirm the feasibility of generating far-UVC, paving the way for mass production in a compact form factor. This solid-state far-UVC laser source shows significant potential for applications in human-safe disinfection, non-line-of-sight free-space communication, and deep-UV Raman spectroscopy.
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Affiliation(s)
- Eric J Stanton
- EMode Photonix, Boulder, CO, USA.
- National Institute of Standards and Technology, Boulder, CO, USA.
- Department of Physics, University of Colorado, Boulder, CO, USA.
| | | | - Emil Z Ulsig
- UVL A/S, Aarhus, Denmark
- Department of Electrical and Computer Engineering, Aarhus University, Aarhus, Denmark
| | | | | | - Simon T Thomsen
- UVL A/S, Aarhus, Denmark
- Department of Electrical and Computer Engineering, Aarhus University, Aarhus, Denmark
| | - Kevin B Gravesen
- UVL A/S, Aarhus, Denmark
- Department of Electrical and Computer Engineering, Aarhus University, Aarhus, Denmark
| | | | - Nicolas Volet
- UVL A/S, Aarhus, Denmark
- Department of Electrical and Computer Engineering, Aarhus University, Aarhus, Denmark
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11
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Bratu DV, Zolya MA, Moraru SA. RoboCoV Cleaner: An Indoor Autonomous UV-C Disinfection Robot with Advanced Dual-Safety Systems. SENSORS (BASEL, SWITZERLAND) 2024; 24:974. [PMID: 38339691 PMCID: PMC11154280 DOI: 10.3390/s24030974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/21/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024]
Abstract
In the face of today's ever-evolving global health landscape and ambient assisted living (AAL), marked by the persistent emergence of novel viruses and diseases that impact vulnerable categories and individual safety, the need for innovative disinfection solutions has surged to unprecedented levels. In pursuit of advancing the field of autonomous UV-C disinfection robotics, we conducted two comprehensive state-of-the-art analyses: the first one in the literature and the second one in existing commercial disinfection robots to identify current challenges. Of all of the challenges, we consider the most outstanding ones to be safeguarding humans and animals and understanding the surroundings while operating the disinfection process challenges that we will address in this article. While UV-C lamps have demonstrated their effectiveness in sterilizing air and surfaces, the field of autonomous UV-C disinfection robotics represents a critical domain that requires advancement, particularly in safeguarding the wellbeing of humans and animals during operation. Operating UV-C disinfection robots in close proximity to humans or animals introduces inherent risks, and existing disinfection robots often fall short in incorporating advanced safety systems. In response to these challenges, we propose the RoboCoV Cleaner-an indoor autonomous UV-C disinfection robot equipped with an advanced dual and redundant safety system. This novel approach incorporates multiple passive infrared (PIR) sensors and AI object detection on a 360-degree camera. Under our test, the dual-redundant system reached more than 90% when detecting humans with high accuracy using the AI system 99% up to 30 m away in a university hallway (different light conditions) combined with the PIR system (with lower accuracy). The PIR system was proved to be a redundant system for uninterrupted operation during communication challenges, ensuring continuous sensor information collection with a swift response time of 50 ms (image processing within 200 ms). It empowers the robot to detect and react to human presence, even under challenging conditions, such as when individuals wear masks, in complete darkness, under UV light, or in environments with blurred visual conditions. In our test, the detection system performed outstandingly well with up to 99% detection rate of humans. Beyond safety features, the RoboCoV Cleaner can identify objects in its surroundings. This capability empowers the robot to discern objects affected by UV-C light, enabling it to apply specialized rules for targeted disinfection. The proposed system exhibits a wide range of capabilities beyond its core purpose of disinfection, making it suitable for healthcare facilities, universities, conference venues, and hospitals. Its implementation has the ability to improve significantly human safety and protect people. By showcasing the RoboCoV Cleaner's safety-first approach and adaptability, we aim to set a new benchmark for UV-C disinfection robots, promoting clean and secure environments while protecting vulnerable people, even in challenging scenarios.
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Affiliation(s)
- Dragoș-Vasile Bratu
- Department of Automatics and Information Technology, Transilvania University of Brasov, 500036 Brașov, Romania; (M.-A.Z.); (S.-A.M.)
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12
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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] [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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13
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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. ENVIRONMENTAL RESEARCH 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] [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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14
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Kousha O, O'Mahoney P, Hammond R, Wood K, Eadie E. 222 nm Far-UVC from filtered Krypton-Chloride excimer lamps does not cause eye irritation when deployed in a simulated office environment. Photochem Photobiol 2024; 100:137-145. [PMID: 37029739 PMCID: PMC10952573 DOI: 10.1111/php.13805] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 04/09/2023]
Abstract
Far-UVC, from filtered Krypton-Chloride lamps, is promising for reducing airborne transmission of disease. While significant research has been undertaken to investigate skin safety of these lamps, less work has been undertaken on eye safety. There is limited data on human eye safety or discomfort from the deployment of this germicidal technology. In this pilot study, immediate and delayed eye discomfort were assessed in a simulated office environment with deployment of Krypton-Chloride lamps, located on the ceiling and directed downwards into the occupied room. Discomfort was assessed immediately postexposure and several days after exposure using validated, Standard Patient Evaluation Eye Dryness (SPEED) and Ocular Surface Disease Index (OSDI) questionnaires. Our results show no significant eye discomfort or adverse effects from the deployment of Far-UVC in this simulated office environment, even when lamps were operated continuously with participants receiving head exposures of up to 50 mJ cm-2 . In addition, a statistically significant reduction in bacteria and fungi of 52% was observed. Far-UVC in this simulated office environment did not cause any clinically significant eye discomfort and was effective at reducing pathogens in the room. These results contribute an important step to further investigation of the interaction of Far-UVC with the human eye.
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Affiliation(s)
- Obaid Kousha
- School of MedicineUniversity of St AndrewsSt AndrewsUK
| | | | | | - Kenneth Wood
- SUPA, School of Physics and AstronomyUniversity of St AndrewsSt AndrewsUK
| | - Ewan Eadie
- Photobiology Unit, NHS TaysideNinewells Hospital and Medical SchoolDundeeUK
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15
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Wang Y, Ma B, Zhao J, Tang Z, Li W, He C, Xia D, Linden KG, Yin R. Rapid Inactivation of Fungal Spores in Drinking Water by Far-UVC Photolysis of Free Chlorine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21876-21887. [PMID: 37978925 DOI: 10.1021/acs.est.3c05703] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Effective and affordable disinfection technology is one key to achieving Sustainable Development Goal 6. In this work, we develop a process by integrating Far-UVC irradiation at 222 nm with free chlorine (UV222/chlorine) for rapid inactivation of the chlorine-resistant and opportunistic Aspergillus niger spores in drinking water. The UV222/chlorine process achieves a 5.0-log inactivation of the A. niger spores at a chlorine dosage of 3.0 mg L-1 and a UV fluence of 30 mJ cm-2 in deionized water, tap water, and surface water. The inactivation rate constant of the spores by the UV222/chlorine process is 0.55 min-1, which is 4.6-fold, 5.5-fold, and 1.8-fold, respectively, higher than those of the UV222 alone, chlorination alone, and the conventional UV254/chlorine process under comparable conditions. The more efficient inactivation by the UV222/chlorine process is mainly attributed to the enhanced generation of reactive chlorine species (e.g., 6.7 × 10-15 M of Cl•) instead of hydroxyl radicals from UV222 photolysis of chlorine, which is verified through both experiments and a kinetic model. We further demonstrate that UV222 photolysis damages the membrane integrity and benefits the penetration of chlorine and radicals into cells for inactivation. The merits of the UV222/chlorine process over the UV254/chlorine process also include the more effective inhibition of the photoreactivation of the spores after disinfection and the lower formation of chlorinated disinfection byproducts and toxicity.
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Affiliation(s)
- Yongyi Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong
| | - Ben Ma
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Jing Zhao
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong
| | - Zhuoyun Tang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Wanxin Li
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou 215000, China
| | - Chun He
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Dehua Xia
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong
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16
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Zhao J, Shang C, Yin R. A High-Radical-Yield Advanced Oxidation Process Coupling Far-UVC Radiation with Chlorinated Cyanurates for Micropollutant Degradation in Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18867-18876. [PMID: 37158565 DOI: 10.1021/acs.est.3c00255] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Increasing the radical yield and reducing energy consumption would enhance the sustainability and competitiveness of advanced oxidation processes (AOPs) for micropollutant degradation in water. We herein report a novel AOP coupling far-UVC radiation at 222 nm with chlorinated cyanurates (termed the UV222/Cl-cyanurates AOP) for radical generation and micropollutant abatement in water. We experimentally determined the concentrations of HO•, Cl•, and ClO• in the UV222/Cl-cyanurates AOP in deionized water and swimming pool water. The radical concentrations are 10-27 times and 4-13 times, respectively, higher than those in the UV254/Cl-cyanurates AOP and the well-documented UV254/chlorine AOP under comparable conditions (e.g., same UV fluence and oxidant dosing). We determined the molar absorption coefficients and innate quantum yields of two chlorine species and two Cl-cyanurates at 222 nm and incorporated these parameters into a kinetic model. The model enables accurate prediction of oxidant photodecay rates as well as the pH impact on radical generation in the UV222/Cl-cyanurates AOP. We predicted the pseudo-first-order degradation rate constants of 25 micropollutants in the UV222/Cl-cyanurates AOP and demonstrated that many micropollutants can be degraded by >80% with a low UV fluence of 25 mJ cm-2. This work advances the fundamental photochemistry of chlorine and Cl-cyanurates at 222 nm and offers a highly effective engineering tool in combating micropollutants in water where Cl-cyanurates are suitable to use.
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Affiliation(s)
- Jing Zhao
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Chii Shang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
- Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
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Liu B, Mullen L, Payne EM, Linden KG. Accelerated Ultraviolet Treatment of Carbamazepine and NDMA in Water under 222 nm Irradiation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18909-18917. [PMID: 37186817 DOI: 10.1021/acs.est.3c00703] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Krypton chloride (KrCl*) excimer ultraviolet (UV) light may provide advantages for contaminant degradation compared to conventional low-pressure (LP) UV. Direct and indirect photolysis as well as UV/hydrogen peroxide-driven advanced oxidation (AOP) of two chemical contaminants were investigated in laboratory grade water (LGW) and treated secondary effluent (SE) for LPUV and filtered KrCl* excimer lamps emitting at 254 and 222 nm, respectively. Carbamazepine (CBZ) and N-nitrosodimethylamine (NDMA) were chosen because of their unique molar absorption coefficient profiles, quantum yields (QYs) at 254 nm, and reaction rate constants with hydroxyl radical. Quantum yields and molar absorption coefficients at 222 nm for both CBZ and NDMA were determined, with measured molar absorption coefficients of 26 422 and 8170 M-1 cm-1, respectively, and QYs of 1.95 × 10-2 and 6.68 × 10-1 mol Einstein-1, respectively. The 222 nm irradiation of CBZ in SE improved degradation compared to that in LGW, likely through promotion of in situ radical formation. AOP conditions improved degradation of CBZ in LGW for both UV LP and KrCl* sources but did not improve NDMA decay. In SE, photolysis of CBZ resulted in decay similar to that of AOP, likely due to the in situ generation of radicals. Overall, the KrCl* 222 nm source significantly improves contaminant degradation compared to that of 254 nm LPUV.
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Affiliation(s)
- Bryan Liu
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, Colorado 80303, United States
| | - Lauren Mullen
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, Colorado 80303, United States
| | - Emma M Payne
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, Colorado 80303, United States
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, Colorado 80303, United States
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18
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Lara de Larrea J, MacIsaac SA, Rauch KD, Stoddart AK, Gagnon GA. Comparison of Legionella pneumophila and Pseudomonas fluorescens Quantification Methods for Assessing UV LED Disinfection. ACS ES&T WATER 2023; 3:3667-3675. [PMID: 37970541 PMCID: PMC10644340 DOI: 10.1021/acsestwater.3c00428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/17/2023]
Abstract
This study assesses the efficacy of ultraviolet light-emitting diodes (UV LEDs) for deactivating Legionella pneumophila (pure culture) and Pseudomonas fluorescens (pure culture and biofilms) on relevant drinking water distribution system surfaces (cast iron and stainless steel). UV LED treatment at 280 nm demonstrated superior performance compared to that at 365 nm, achieving a 4.8 log reduction value (LRV) for P. fluorescens pure cultures and, for biofilms, 4.02 LRV for stainless steel and 2.96 LRV for cast iron at 280 nm. Conversely, the results were less effective at 365 nm, with suspected photolytic reactions on cast iron. Quantification of L. pneumophila yielded varying results: 4 LRV using standard plate counts, 1.8 LRV with Legiolert, and 1 LRV with quantitative polymerase chain reaction at 280 nm, while the results were less than 1.5 LRV at 365 nm. This study provides insights into managing opportunistic pathogens and biofilms, emphasizing the need for improved quantification tools to better assess treatment efficacy.
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Affiliation(s)
- Jaser Lara de Larrea
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Sean A. MacIsaac
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Kyle D. Rauch
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Amina K. Stoddart
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Graham A. Gagnon
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
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Otaka Y, Izawa M, Sakagami H, Shiba N, Takahashi N, Tanuma SI, Amano S, Uota S, Inomata M, Yokose S, Sunaga K, Hayashi S, Koga-Ogawa Y, Nakaya G, Kito S. UVC-Protective Activity of Lemongrass Among 12 Fat-soluble Herbal Extracts: Rapid Decay Due to Cytotoxicity. In Vivo 2023; 37:2464-2472. [PMID: 37905640 PMCID: PMC10621405 DOI: 10.21873/invivo.13353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 11/02/2023]
Abstract
BACKGROUND/AIM The COVID-19 pandemic led to the rapid spread of the use of ultraviolet C (UVC) sterilizers in many public facilities. Considering the harmful effects of prolonged exposure to UVC, manufacturing of safe skin care products is an important countermeasure. In continuation of our recent study of water-soluble herbal extracts, the present study aimed at searching for anti-UVC components from fat-soluble herbal extracts. MATERIALS AND METHODS Human dermal fibroblast and melanoma cells were exposed to UVC (1.193 W/m2) for 3 min. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell-cycle analysis was performed using a cell sorter. UVC-protective activity was quantified by the selective index (SI), i.e., the ratio of the 50% cytotoxic concentration for unirradiated cells to the concentration that restored viability of UVC-treated cells by 50%. RESULTS Only lemongrass extract, among 12 fat-soluble herbal extracts, showed significant anti-UVC activity, comparable to that of lignified materials and tannins, but exceeding that of N-acetyl-L-cysteine and resveratrol. Lemongrass extract was highly cytotoxic, producing a subG1 cell population. During prolonged incubation in culture medium, the anti-UVC activity of lemongrass extract, sodium ascorbate and vanillic acid declined with an approximate half-life of <0.7, 5.4-21.6, and 27.8-87.0 h, respectively. CONCLUSION Removal of cytotoxic principle(s) from lemongrass extract is crucial to producing long-lasting UVC-protective effects.
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Affiliation(s)
- Yusei Otaka
- Division of Dental Radiology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan;
| | - Maki Izawa
- Division of Dental Radiology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan
| | - Hiroshi Sakagami
- Meikai University Research Institute of Odontology (M-RIO), Saitama, Japan
| | - Noriyoshi Shiba
- Division of Dental Radiology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan
| | - Nobutoshi Takahashi
- Division of Dental Radiology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan
| | - Sei-Ichi Tanuma
- Meikai University Research Institute of Odontology (M-RIO), Saitama, Japan
| | - Shigeru Amano
- Meikai University Research Institute of Odontology (M-RIO), Saitama, Japan
| | - Shin Uota
- Meikai University Research Institute of Odontology (M-RIO), Saitama, Japan
| | - Megumi Inomata
- Division of Microbiology and Immunology, Department of Oral Biology and Tissue Engineering, Meikai University School of Dentistry, Saitama, Japan
| | - Satoshi Yokose
- Division of Endodontics and Operative Dentistry, Department of Restorative and Biomaterials Sciences, Meikai University School of Dentistry, Saitama, Japan
| | - Katsuyoshi Sunaga
- Laboratory of Pharmacotherapy, Graduate School of Pharmaceutical Sciences, Josai University, Saitama, Japan
| | | | - Yukari Koga-Ogawa
- Faculty of Health Sciences, Nihon Institute of Medical Science, Saitama, Japan
| | - Giichirou Nakaya
- Faculty of Health Sciences, Nihon Institute of Medical Science, Saitama, Japan
| | - Shinji Kito
- Division of Dental Radiology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan
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20
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Ning P, Han Y, Liu Y, Liu S, Sun Z, Wang X, Wang B, Gao F, Wang Y, Wang Y, Gao X, Chen G, Li X. Study on disinfection effect of a 222-nm UVC excimer lamp on object surface. AMB Express 2023; 13:102. [PMID: 37752386 PMCID: PMC10522550 DOI: 10.1186/s13568-023-01611-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 09/19/2023] [Indexed: 09/28/2023] Open
Abstract
Effective disinfection of contaminated surfaces is essential for preventing the transmission of pathogens. In this study, we investigated the UV irradiance and wavelength distribution of a 222-nm ultraviolet C (UVC) excimer lamp and its disinfection efficacy against microorganisms in laboratory conditions. By using a carrier quantitative germicidal test with stainless steel sheets as carriers, we examined the disinfection effect of the 222-nm UVC lamp on three standard strains-Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. We tested the disinfection efficacy under different conditions by adjusting irradiation time, as well as the state and temperature of the stainless steel carriers. Our results indicated that a bacterial suspension in PBS and not-dried stainless steel carriers yielded better disinfection than in TSB and dried carriers. Additionally, carrier temperature had no significant impact on disinfection efficacy. When utilizing a bacterial suspension in PBS and non-dried carriers at a temperature of 20 °C, the three bacteria were eliminated by 222-nm UVC excimer lamp irradiation in just 15 s. In contrast, when using a bacterial suspension in TSB and dried carriers at temperatures of 20 °C, 4 °C, or - 20 °C, the three bacteria were eradicated by 222-nm UVC excimer lamp irradiation in 60 s. Comparatively, the LPM lamp required more than 10 min to achieve the same disinfection effect. Our data demonstrate that the 222-nm UVC excimer lamp has higher irradiance and a more potent microbial disinfection effect than the LPM lamp, requiring significantly less irradiation time to achieve the same disinfection effect under identical conditions. Furthermore, the 222-nm UVC excimer lamp exhibited a substantial disinfection effect on bacterial propagules at low temperatures. Our findings support the optimization of "tunnel-type" cold-chain goods disinfection devices, providing an alternative, highly efficient, and practical tool to combat the spread of SARS-CoV-2 through cold-chain systems.
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Affiliation(s)
- Peiyong Ning
- Tianjin Centers for Disease Control and Prevention-Institute of Microbiology, Tianjin, 300011, China.
- Tianjin Key Laboratory of Pathogenic Microbiology of Infectious Disease, Tianjin Centers for Disease Control and Prevention, Tianjin, 300011, China.
| | - Yanzhen Han
- Tianjin Centers for Disease Control and Prevention-Institute of Microbiology, Tianjin, 300011, China
- Tianjin Key Laboratory of Pathogenic Microbiology of Infectious Disease, Tianjin Centers for Disease Control and Prevention, Tianjin, 300011, China
| | - Yang Liu
- Animal, Plant and Foodstuffs Inspection Centre of Tianjin Customs, Tianjin, 300457, China
| | - Shengchun Liu
- Tianjin University of Commerce, Tianjin, 300134, China
| | - Zhili Sun
- Tianjin University of Commerce, Tianjin, 300134, China
| | - Xinru Wang
- Tianjin University of Commerce, Tianjin, 300134, China
| | - Baiqi Wang
- Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin, 300070, China
- Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, 300070, China
| | - Feng Gao
- Tianjin Bureau of Commerce, Tianjin, 300040, China
| | - Ying Wang
- Tianjin Centers for Disease Control and Prevention-Institute of Microbiology, Tianjin, 300011, China
- Tianjin Key Laboratory of Pathogenic Microbiology of Infectious Disease, Tianjin Centers for Disease Control and Prevention, Tianjin, 300011, China
| | - Yuan Wang
- Tianjin Centers for Disease Control and Prevention-Institute of Microbiology, Tianjin, 300011, China
- Tianjin Key Laboratory of Pathogenic Microbiology of Infectious Disease, Tianjin Centers for Disease Control and Prevention, Tianjin, 300011, China
| | - Xin Gao
- Tianjin Centers for Disease Control and Prevention-Institute of Microbiology, Tianjin, 300011, China
- Tianjin Key Laboratory of Pathogenic Microbiology of Infectious Disease, Tianjin Centers for Disease Control and Prevention, Tianjin, 300011, China
| | - Guanyi Chen
- Tianjin University of Commerce, Tianjin, 300134, China
| | - Xiaoyan Li
- Tianjin Centers for Disease Control and Prevention-Institute of Microbiology, Tianjin, 300011, China.
- Tianjin Key Laboratory of Pathogenic Microbiology of Infectious Disease, Tianjin Centers for Disease Control and Prevention, Tianjin, 300011, China.
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21
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Seyedi S, Ma B, Groves M, King H, Linden KG. Field Study and Evaluation of KrCl* Far UV-C Device Capability for Inactivation of Phi6 Bacteriophage. Photochem Photobiol 2023; 99:1293-1298. [PMID: 36533876 DOI: 10.1111/php.13767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
"Far UV-C" is an effective disinfection method that can be deployed in occupied areas. Commercially available Krypton Chloride (KrCl*) excimer lamps filtered to emit at 222 nm are effective in disinfecting pathogens and safe for human exposure up to an allowable threshold exposure, which is much longer than for conventional UV lamps emitting at 254 nm. Laboratory and controlled field testing of a filtered KrCl* excimer lamp for disinfection of a virus suspended in a thin film aqueous solution in an occupied office setting was conducted. Complete inactivation of almost 6 log (99.9999%) of Phi6 bacteriophage virus was achieved in ~20 min of exposure time in a field setting, equivalent to a dose of about 10 mJ cm-2 . The Phi6 inactivation rate constant for the field test results were not statistically different from laboratory values (P > 0.05, paired t-test). When positioned at 1 m distance from possible human exposure, this device can be used safely for almost 4.5 h of continuous direct exposure without any acute or long-term adverse health effects. This study illustrates the applicability and deployment of Far UV-C for pathogen reduction and can help in decision making for implementation of Far UV-C for disinfection in human-occupied environments.
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Affiliation(s)
- Saba Seyedi
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO
- Hazen and Sawyer, Fairfax, VA
| | - Ben Ma
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO
| | - Megan Groves
- Population Lights, Inc. d/b/a Population, San Francisco, CA
| | - Hal King
- Public Health Innovations, Saint Simons Island, GA
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, CO
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22
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Maubert B, Theillière C, Jany P, Bourlet T, Deschamps J, Pozzetto B, Singh F, Gadea E. Ultrafast inactivation of SARS-CoV-2 by 254-nm UV-C irradiation on porous and non-porous media of medical interest using an omnidirectional chamber. Sci Rep 2023; 13:12648. [PMID: 37542073 PMCID: PMC10403608 DOI: 10.1038/s41598-023-39439-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 07/25/2023] [Indexed: 08/06/2023] Open
Abstract
Covid-19 has spurred a renewed interest in decontamination techniques for air, objects and surfaces. Beginning in 2020, urgent effort was done to permit the reuse of UV-C for inactivating SARS-CoV-2. However, those studies diverged widely on the dose necessary to reach this goal; until today, the real value of the sensitivity of the virus to a 254-nm illumination is not known precisely. In this study, decontamination was performed in an original UV-C large decontamination chamber (UVCab, ON-LIGHT, France) delivering an omnidirectional irradiation with an average dose of 50 mJ/cm2 in 60 s. Viral inactivation was checked by both cell culture and PCR test. SARS-CoV-2 was inactivated by UV-C light within 3 s on both porous (disposable gown) and non-porous (stainless steel and apron) surfaces. For the porous surface, an irradiation of 5 min was needed to achieve a completely negative PCR signal. The Z value estimating the sensitivity of SARS-CoV-2 to UV-C in the experimental conditions of our cabinet was shown to be > 0.5820 m2/J. These results illustrate the ability of this apparatus to inactivate rapidly and definitively high loads of SARS-CoV-2 deposited on porous or non-porous supports and opens new perspectives on material decontamination using UV-C.
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Affiliation(s)
- Bertrand Maubert
- Laboratoire de Biologie, Centre Hospitalier Emile Roux, 43000, Le Puy en Velay, France
| | - Camille Theillière
- Unité de Recherche Clinique, Centre Hospitalier Emile Roux, 43000, Le Puy en Velay, France
- CIRI, Centre International de Recherche en Infectiologie, GIMAP Team, Univ St-Etienne, INSERM U1111, CNRS UMR5308, ENS de Lyon, UCBL1, Univ Lyon, 42023, Saint-Etienne, France
| | - Prescillia Jany
- Unité de Recherche Clinique, Centre Hospitalier Emile Roux, 43000, Le Puy en Velay, France
| | - Thomas Bourlet
- CIRI, Centre International de Recherche en Infectiologie, GIMAP Team, Univ St-Etienne, INSERM U1111, CNRS UMR5308, ENS de Lyon, UCBL1, Univ Lyon, 42023, Saint-Etienne, France
- Service des Agents Infectieux, Centre Hospitalier Universitaire de Saint-Étienne, 42055, Saint-Etienne, France
| | - Jérôme Deschamps
- ON-LIGHT SAS, SMO Biopole Clermont-Limagne, 63360, Saint Beauzire, France
| | - Bruno Pozzetto
- CIRI, Centre International de Recherche en Infectiologie, GIMAP Team, Univ St-Etienne, INSERM U1111, CNRS UMR5308, ENS de Lyon, UCBL1, Univ Lyon, 42023, Saint-Etienne, France
- Service des Agents Infectieux, Centre Hospitalier Universitaire de Saint-Étienne, 42055, Saint-Etienne, France
| | - Fateh Singh
- ON-LIGHT SAS, SMO Biopole Clermont-Limagne, 63360, Saint Beauzire, France
| | - Emilie Gadea
- Unité de Recherche Clinique, Centre Hospitalier Emile Roux, 43000, Le Puy en Velay, France.
- U1059, Equipe DVH, Mines Saint-Etienne, Univ Lyon, Univ St-Etienne, 42000, Saint-Etienne, France.
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23
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Sun W, Jing Z, Zhao Z, Yin R, Santoro D, Mao T, Lu Z. Dose-Response Behavior of Pathogens and Surrogate Microorganisms across the Ultraviolet-C Spectrum: Inactivation Efficiencies, Action Spectra, and Mechanisms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:10891-10900. [PMID: 37343195 DOI: 10.1021/acs.est.3c00518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
The dose-response behavior of pathogens and inactivation mechanisms by UV-LEDs and excimer lamps remains unclear. This study used low-pressure (LP) UV lamps, UV-LEDs with different peak wavelengths, and a 222 nm krypton chlorine (KrCl) excimer lamp to inactivate six microorganisms and to investigate their UV sensitivities and electrical energy efficiencies. The 265 nm UV-LED had the highest inactivation rates (0.47-0.61 cm2/mJ) for all tested bacteria. The bacterial sensitivity strongly fitted the absorption curve of nucleic acids at wavelengths of 200-300 nm; however, indirect damage induced by reactive oxygen species (ROS) was the leading cause of bacterial inactivation under 222 nm UV irradiation. In addition, the guanine and cytosine (GC) content and cell wall constituents of bacteria affect inactivation efficiency. The inactivation rate constant of Phi6 (0.13 ± 0.002 cm2/mJ) at 222 nm due to lipid envelope damage was significantly higher than other UVC (0.006-0.035 cm2/mJ). To achieve 2log reduction, the LP UV lamp had the best electrical energy efficiency (required less energy, average 0.02 kWh/m3) followed by 222 nm KrCl excimer lamp (0.14 kWh/m3) and 285 nm UV-LED (0.49 kWh/m3).
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Affiliation(s)
- Wenjun Sun
- School of Environment, Tsinghua University, Beijing 100084, China
- Research Institute for Environmental Innovation (Suzhou) Tsinghua, Suzhou 215163, China
| | - Zibo Jing
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Zhinan Zhao
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999066, PR China
| | | | - Ted Mao
- Research Institute for Environmental Innovation (Suzhou) Tsinghua, Suzhou 215163, China
- MW Technologies, Inc., London, Ontario L8N1E, Canada
| | - Zedong Lu
- School of Environment, Tsinghua University, Beijing 100084, China
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24
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Li LX, Nissly RH, Swaminathan A, Bird IM, Boyle NR, Nair MS, Greenawalt DI, Gontu A, Cavener VS, Sornberger T, Freihaut JD, Kuchipudi SV, Bahnfleth WP. Inactivation of HCoV-NL63 and SARS-CoV-2 in aqueous solution by 254 nm UV-C. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2023; 245:112755. [PMID: 37423001 DOI: 10.1016/j.jphotobiol.2023.112755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/29/2023] [Accepted: 07/03/2023] [Indexed: 07/11/2023]
Abstract
Ultraviolet germicidal irradiation (UVGI) is a highly effective means of inactivating many bacteria, viruses, and fungi. UVGI is an attractive viral mitigation strategy against coronaviruses, including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the coronavirus disease-2019 (COVID-19) pandemic. This investigation measures the susceptibility of two human coronaviruses to inactivation by 254 nm UV-C radiation. Human coronavirus NL63 and SARS-CoV-2 were irradiated in a collimated, dual-beam, aqueous UV reactor. By measuring fluence and integrating it in real-time, this reactor accounts for the lamp output transients during UVGI exposures. The inactivation rate constants of a one-stage exponential decay model were determined to be 2.050 cm2/mJ and 2.098 cm2/mJ for the NL63 and SARS-CoV-2 viruses, respectively. The inactivation rate constant for SARS-CoV-2 is within 2% of that of NL63, indicating that in identical inactivation environments, very similar UV 254 nm deactivation susceptibilities for these two coronaviruses would be achieved. Given the inactivation rate constant obtained in this study, doses of 1.1 mJ/cm2, 2.2 mJ/cm2, and 3.3 mJ/cm2 would result in a 90%, 99%, and 99.9% inactivation of the SARS-CoV-2 virus, respectively. The inactivation rate constant obtained in this study is significantly higher than values reported from many 254 nm studies, which suggests greater UV susceptibility to the UV-C than what was believed. Overall, results from this study indicate that 254 nm UV-C is effective for inactivation of human coronaviruses, including SARS-CoV-2.
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Affiliation(s)
- Lily X Li
- Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA, 16802, United States of America
| | - Ruth H Nissly
- Pennsylvania State University, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, University Park, PA 16802, United States of America
| | - Anand Swaminathan
- Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA, 16802, United States of America
| | - Ian M Bird
- Pennsylvania State University, Huck Institutes of the Life Sciences, University Park, PA 16802, United States of America
| | - Nina R Boyle
- Pennsylvania State University, Huck Institutes of the Life Sciences, University Park, PA 16802, United States of America
| | - Meera Surendran Nair
- Pennsylvania State University, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, University Park, PA 16802, United States of America
| | - Denver I Greenawalt
- Pennsylvania State University, Huck Institutes of the Life Sciences, University Park, PA 16802, United States of America
| | - Abhinay Gontu
- Pennsylvania State University, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, University Park, PA 16802, United States of America
| | - Victoria S Cavener
- Pennsylvania State University, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, University Park, PA 16802, United States of America
| | - Ty Sornberger
- Pennsylvania State University, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, University Park, PA 16802, United States of America
| | - James D Freihaut
- Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA, 16802, United States of America.
| | - Suresh V Kuchipudi
- Pennsylvania State University, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, University Park, PA 16802, United States of America; Pennsylvania State University, Huck Institutes of the Life Sciences, University Park, PA 16802, United States of America.
| | - William P Bahnfleth
- Pennsylvania State University, Department of Architectural Engineering, 104 Engineering Unit A, University Park, PA, 16802, United States of America.
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25
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Takamure K, Iwatani Y, Amano H, Yagi T, Uchiyama T. Inactivation characteristics of a 280 nm Deep-UV irradiation dose on aerosolized SARS-CoV-2. ENVIRONMENT INTERNATIONAL 2023; 177:108022. [PMID: 37301046 PMCID: PMC10241504 DOI: 10.1016/j.envint.2023.108022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/03/2023] [Accepted: 06/03/2023] [Indexed: 06/12/2023]
Abstract
A non-filter virus inactivation unit was developed that can control the irradiation dose of aerosolized viruses by controlling the lighting pattern of a 280 nm deep-UV (DUV)-LED and the air flowrate. In this study, the inactivation properties of aerosolized SARS-CoV-2 were quantitatively evaluated by controlling the irradiation dose to the virus inside the inactivation unit. The RNA concentration of SARS-CoV-2 remained constant when the total irradiation dose of DUV irradiation to the virus exceeded 16.5 mJ/cm2. This observation suggests that RNA damage may occur in regions below the detection threshold of RT-qPCR assay. However, when the total irradiation dose was less than 16.5 mJ/cm2, the RNA concentration monotonically increased with a decreasing LED irradiation dose. However, the nucleocapsid protein concentration of SARS-CoV-2 was not predominantly dependent on the LED irradiation dose. The plaque assay showed that 99.16% of the virus was inactivated at 8.1 mJ/cm2 of irradiation, and no virus was detected at 12.2 mJ/cm2 of irradiation, resulting in a 99.89% virus inactivation rate. Thus, an irradiation dose of 23% of the maximal irradiation capacity of the virus inactivation unit can activate more than 99% of SARS-CoV-2. These findings are expected to enhance versatility in various applications. The downsizing achieved in our study renders the technology apt for installation in narrow spaces, while the enhanced flowrates establish its viability for implementation in larger facilities.
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Affiliation(s)
- Kotaro Takamure
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan.
| | - Yasumasa Iwatani
- Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya 460-0001, Japan
| | - Hiroshi Amano
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan
| | - Tetsuya Yagi
- Department of Infectious Diseases, Nagoya University Hospital, Nagoya 466-0065, Japan
| | - Tomomi Uchiyama
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan
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26
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Pereira AR, Braga DFO, Vassal M, Gomes IB, Simões M. Ultraviolet C irradiation: A promising approach for the disinfection of public spaces? THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:163007. [PMID: 36965719 DOI: 10.1016/j.scitotenv.2023.163007] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/10/2023] [Accepted: 03/18/2023] [Indexed: 05/17/2023]
Abstract
Ultraviolet irradiation C (UVC) has emerged as an effective strategy for microbial control in indoor public spaces. UVC is commonly applied for air, surface, and water disinfection. Unlike common 254 nm UVC, far-UVC at 222 nm is considered non-harmful to human health, being safe for occupied spaces, and still effective for disinfection purposes. Therefore, and allied to the urgency to mitigate the current pandemic of SARS-CoV-2, an increase in UVC-based technology devices appeared in the market with levels of pathogens reduction higher than 99.9 %. This environmentally friendly technology has the potential to overcome many of the limitations of traditional chemical-based disinfection approaches. The novel UVC-based devices were thought to be used in public indoor spaces such as hospitals, schools, and public transport to minimize the risk of pathogens contamination and propagation, saving costs by reducing manual cleaning and equipment maintenance provided by manpower. However, a lack of information about UVC-based parameters and protocols for disinfection, and controversies regarding health and environmental risks still exist. In this review, fundamentals on UVC disinfection are presented. Furthermore, a deep analysis of UVC-based technologies available in the market for the disinfection of public spaces is addressed, as well as their advantages and limitations. This comprehensive analysis provides valuable inputs and strategies for the development of effective, reliable, and safe UVC disinfection systems.
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Affiliation(s)
- Ana Rita Pereira
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Daniel F O Braga
- SpinnerDynamics, Lda., Rua da Junta de Freguesia 194, Escariz, 4540-322 Arouca, Portugal
| | - Mariana Vassal
- SpinnerDynamics, Lda., Rua da Junta de Freguesia 194, Escariz, 4540-322 Arouca, Portugal
| | - Inês B Gomes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Manuel Simões
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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27
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Fujimoto N, Nagaoka K, Tatsuno I, Oishi H, Tomita M, Hasegawa T, Tanaka Y, Matsumoto T. Wavelength dependence of ultraviolet light inactivation for SARS-CoV-2 omicron variants. Sci Rep 2023; 13:9706. [PMID: 37322228 PMCID: PMC10272214 DOI: 10.1038/s41598-023-36610-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 06/07/2023] [Indexed: 06/17/2023] Open
Abstract
Ultraviolet (UV) irradiation offers an effective and convenient method for the disinfection of pathogenic microorganisms. However, UV irradiation causes protein and/or DNA damage; therefore, further insight into the performance of different UV wavelengths and their applications is needed to reduce risks to the human body. In this paper, we determined the efficacy of UV inactivation of the SARS-CoV-2 omicron BA.2 and BA.5 variants in a liquid suspension at various UV wavelengths by the 50% tissue culture infection dose (TCID50) method and quantitative polymerase chain reaction (qPCR) assay. The inactivation efficacy of 220 nm light, which is considered safe for the human body, was approximately the same as that of health hazardous 260 nm light for both BA.2 and BA.5. Based on the inactivation rate constants determined by the TCID50 and qPCR methods versus the UV wavelength, the action spectra were determined, and BA.2 and BA.5 showed almost the same spectra. This result suggests that both variants have the same UV inactivation characteristics.
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Affiliation(s)
- Nahoko Fujimoto
- Department of Gastroenterology and Hepatology, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan
| | - Katsuya Nagaoka
- Department of Gastroenterology and Hepatology, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan
| | - Ichiro Tatsuno
- Graduate School of Medical Sciences, Nagoya City University, Nagoya, 467-8601, Japan
| | - Hisashi Oishi
- Graduate School of Medical Sciences, Nagoya City University, Nagoya, 467-8601, Japan
| | - Makoto Tomita
- Department of Physics, Faculty of Science, Shizuoka University, Shizuoka, 422-8529, Japan
| | - Tadao Hasegawa
- Graduate School of Medical Sciences, Nagoya City University, Nagoya, 467-8601, Japan
| | - Yasuhito Tanaka
- Department of Gastroenterology and Hepatology, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan
| | - Takahiro Matsumoto
- Department of Gastroenterology and Hepatology, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan.
- Graduate School of Medical Sciences, Nagoya City University, Nagoya, 467-8601, Japan.
- Graduate School of Design and Architecture, Nagoya City University, Nagoya, 464-0083, Japan.
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28
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Xu J, Huang CH. Enhanced Direct Photolysis of Organic Micropollutants by Far-UVC Light at 222 nm from KrCl* Excilamps. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2023; 10:543-548. [PMID: 37333939 PMCID: PMC10269434 DOI: 10.1021/acs.estlett.3c00313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 05/24/2023] [Accepted: 05/24/2023] [Indexed: 06/20/2023]
Abstract
Krypton chloride (KrCl*) excilamps emitting at far-UVC 222 nm represent a promising technology for microbial disinfection and advanced oxidation of organic micropollutants (OMPs) in water treatment. However, direct photolysis rates and photochemical properties at 222 nm are largely unknown for common OMPs. In this study, we evaluated photolysis for 46 OMPs by a KrCl* excilamp and compared it with a low-pressure mercury UV lamp. Generally, OMP photolysis was greatly enhanced at 222 nm with fluence rate-normalized rate constants of 0.2-21.6 cm2·μEinstein-1, regardless of whether they feature higher or lower absorbance at 222 nm than at 254 nm. The photolysis rate constants and quantum yields were 10-100 and 1.1-47 times higher, respectively, than those at 254 nm for most OMPs. The enhanced photolysis at 222 nm was mainly caused by strong light absorbance for non-nitrogenous, aniline-like, and triazine OMPs, while notably higher quantum yield (4-47 times of that at 254 nm) occurred for nitrogenous OMPs. At 222 nm, humic acid can inhibit OMP photolysis by light screening and potentially by quenching intermediates, while nitrate/nitrite may contribute more than others to screen light. Overall, KrCl* excilamps are promising in achieving effective OMP photolysis and merit further research.
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Affiliation(s)
- Jiale Xu
- Department
of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58102, United States
- School
of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Ching-Hua Huang
- School
of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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29
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Atari N, Mamane H, Silberbush A, Zuckerman N, Mandelboim M, Gerchman Y. Disinfection of SARS-CoV-2 by UV-LED 267 nm: comparing different variants. Sci Rep 2023; 13:8229. [PMID: 37217554 DOI: 10.1038/s41598-023-35247-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 05/15/2023] [Indexed: 05/24/2023] Open
Abstract
UV irradiation is an efficient tool for the disinfection of viruses in general and coronavirus specifically. This study explores the disinfection kinetics of SARS-CoV-2 variants wild type (similar to the Wuhan strain) and three variants (Alpha, Delta, and Omicron) by 267 nm UV-LED. All variants showed more than 5 logs average reduction in copy number at 5 mJ/cm2 but inconsistency was evident, especially for the Alpha variant. Increasing the dose to 7 mJ/cm2 did not increase average inactivation but did result in a dramatic decrease in the inactivation inconsistency making this dose the recommended minimum. Sequence analysis suggests that the difference between the variants is likely due to small differences in the frequency of specific UV extra-sensitive nucleotide sequence motifs although this hypothesis requires further experimental testing. In summary, the use of UV-LED with their simple electricity need (can be operated from a battery or photovoltaic panel) and geometrical flexibility could offer many advantages in the prevention of SARS-CoV-2 spread, but minimal UV dose should be carefully considered.
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Affiliation(s)
- Nofar Atari
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel
| | - Hadas Mamane
- School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Alon Silberbush
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa-Oranim, Kiryat Tiv'on, Israel
| | - Neta Zuckerman
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel
| | - Michal Mandelboim
- Central Virology Laboratory, Ministry of Health, Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel
- Department of Epidemiology and Preventive Medicine, School of Public Health, Tel-Aviv University, Tel Aviv, Israel
| | - Yoram Gerchman
- The Institute of Evolution, University of Haifa, Haifa, Israel.
- Oranim College, 3600600, Tivon, Israel.
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Weyersberg L, Sommerfeld F, Vatter P, Hessling M. UV radiation sensitivity of bacteriophage PhiX174 - A potential surrogate for SARS-CoV-2 in terms of radiation inactivation. AIMS Microbiol 2023; 9:431-443. [PMID: 37649795 PMCID: PMC10462461 DOI: 10.3934/microbiol.2023023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/16/2023] [Accepted: 04/24/2023] [Indexed: 09/01/2023] Open
Abstract
To minimize health risks, surrogates are often employed to reduce experiments with pathogenic microorganisms and the associated health risk. Due to structural similarities between the enveloped RNA-viruses SARS-CoV-2 and Phi6, the latter has been established as a nonpathogenic coronavirus surrogate for many applications. However, large discrepancies in the UV log-reduction doses between SARS-CoV-2 and Phi6 necessitate the search for a better surrogate for UV inactivation applications. A literature study provided the bacteriophage PhiX174 as a potentially more suitable nonpathogenic coronavirus surrogate candidate. In irradiation experiments, the sensitivity of PhiX174 was investigated upon exposure to UV radiation of wavelengths 222 nm (Far-UVC), 254 nm (UVC), 302 nm (broad-band UVB), 311 nm (narrow-band UVB) and 366 nm (UVA) using a plaque assay. The determined log-reduction doses for PhiX174 were 1.3 mJ/cm2 @ 222 nm, 5 mJ/cm2 @ 254 nm, 17.9 mJ/cm2 @ 302 nm, 625 mJ/cm2 @ 311 nm and 42.5 J/cm2 @ 366 nm. The comparison of these results with published log-reduction doses of SARS-CoV-2 in the same spectral region, led to the conclusion that the bacteriophage PhiX174 exhibits larger log-reduction doses than SARS-CoV-2, nevertheless, it is a better UV-surrogate at 222 nm (Far-UVC), 254 nm (UVC) and 302 nm (UVB) than the often applied Phi6.
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Affiliation(s)
| | | | | | - Martin Hessling
- Ulm University of Applied Sciences, Department of Medical Engineering and Mechatronics, Biotech-Lab, Albert Einstein-Allee 55, D-89081 Ulm, Germany
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Ma B, Burke-Bevis S, Tiefel L, Rosen J, Feeney B, Linden KG. Reflection of UVC wavelengths from common materials during surface UV disinfection: Assessment of human UV exposure and ozone generation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161848. [PMID: 36709900 DOI: 10.1016/j.scitotenv.2023.161848] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/22/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
The COVID-19 pandemic has promoted interest in using devices emitting ultraviolet-C (UVC) irradiation (200-280 nm) for surface disinfection to reduce pathogen transmission, especially in occupied public spaces. While UVC devices have been shown to be highly effective against various pathogens, there are safety concerns when using conventional UVC devices for surface disinfection, including human exposure of reflected UVC irradiation and ozone generation. Emerging Far UVC devices (emitting at 200-230 nm), like the krypton chloride (KrCl*) excimer, have the potential to be safely applied in occupied spaces due to their minimal adverse effects on skin and eyes. In this study, UV reflection of 21 common materials was documented and compared using a filtered KrCl* excimer (installed with a bandpass filter at 222 nm), an unfiltered KrCl* excimer, and a conventional low-pressure mercury vapor lamp. The safety of Far UVC devices was evaluated based on the irradiance and spectrum of reflected UV irradiation and ozone generation measured at various locations around the device. Our results show that most common materials can reflect UV irradiation, among which some metals tend to have greater reflection. The Far UVC devices, especially the filtered KrCl* excimer, should be safe to be applied in occupied spaces for effective surface disinfection, with limited ozone generation and no health risk from reflected UV irradiation. However more caution is needed when using unfiltered KrCl* devices and conventional UV 254 nm light. This study provides urgently needed data on UV reflection of common materials and guidance for safety assessments of UVC devices for surface disinfection in occupied spaces.
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Affiliation(s)
- Ben Ma
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Dr., Boulder, CO 80303, United States
| | - Sam Burke-Bevis
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Dr., Boulder, CO 80303, United States
| | - Luke Tiefel
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Dr., Boulder, CO 80303, United States
| | - Jennifer Rosen
- Freestyle Partners, LLC, and its affiliate, FSP Innovations, LLC, MI, United States
| | - Ben Feeney
- Freestyle Partners, LLC, and its affiliate, FSP Innovations, LLC, MI, United States
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Dr., Boulder, CO 80303, United States.
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Kodamatani H, Kubo S, Takeuchi A, Kanzaki R, Tomiyasu T. Sensitive Detection of Nitrite and Nitrate in Seawater by 222 nm UV-Irradiated Photochemical Conversion to Peroxynitrite and Ion Chromatography-Luminol Chemiluminescence System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5924-5933. [PMID: 36973229 DOI: 10.1021/acs.est.3c00273] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Sensitive detection methods for nitrite (NO2-) and nitrate (NO3-) ions are essential to understand the nitrogen cycle and for environmental protection and public health. Herein, we report a detection method that combines ion-chromatographic separation of NO2- and NO3-, on-line photochemical conversion of these ions to peroxynitrite (ONOO-) by irradiation with a 222 nm excimer lamp, and chemiluminescence from the reaction between luminol and ONOO-. The detection limits for NO2- and NO3- were 0.01 and 0.03 μM, respectively, with linear ranges of 0.010-2.0 and 0.10-3.0 μM, respectively, at an injection volume of 1 μL. The results obtained by the proposed method for seawater analysis corresponded with those of a reference method (AutoAnalyzer based on the Griess reaction). As luminol chemiluminescence can measure ONOO- at picomolar concentrations, our method is expected to be able to detect NO2- and NO3- at picomolar concentrations owing to the high conversion ratio to ONOO- (>60%), assuming that contamination and background chemiluminescence issues can be resolved. This method has the potential to emerge as an innovative technology for NO2- and NO3- detection in various samples.
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Affiliation(s)
- Hitoshi Kodamatani
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
| | - Shotaro Kubo
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
| | - Akinori Takeuchi
- Health and Environmental Risk Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Ryo Kanzaki
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
| | - Takashi Tomiyasu
- Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
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Neo Y, Hashimoto G, Koike R, Ohhara T, Matsumoto T. Solid-State Far-Ultraviolet C Light Sources for the Disinfection of Pathogenic Microorganisms Using Graphene Nanostructure Field Emitters. GLOBAL CHALLENGES (HOBOKEN, NJ) 2023; 7:2200236. [PMID: 37020617 PMCID: PMC10069303 DOI: 10.1002/gch2.202200236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/07/2023] [Indexed: 06/19/2023]
Abstract
The ongoing global outbreak of coronavirus disease has necessitated the use of ultraviolet (UV) disinfection techniques to reduce viral transmission in public places. The previously used UV wavelength is harmful to the human body, the wavelength range from 200 to 235 nm, often referred to as far-UVC light, has attracted attention as a novel disinfection wavelength range that can be used in a safe manner. However, the currently used light sources have practical problems, such as an expensive cost, a low efficiency, and short lifetimes. Therefore, environmentally friendly solid-state light sources with a lower cost, higher efficiency, and longer lifetimes are demanded. Here, an efficient mercury-free far-UVC solid-state light source is presented. This light source demonstrates intense 230 nm emission with a narrow spectral width of 30 nm and a long lifetime of more than 1000 h. These characteristics can be achieved by graphene nanostructure field emitters and wide-bandgap magnesium aluminate phosphors. By using this light source, the efficient disinfection of Escherichia coli is demonstrated. The light sources presented here facilitate future technologies for preventing the spread of infectious diseases in a safe and convenient manner.
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Affiliation(s)
- Yoichiro Neo
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
| | - Gai Hashimoto
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
| | - Rei Koike
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
| | - Takashi Ohhara
- Neutron Science SectionJ‐PARC CenterJapan Atomic Energy AgencyIbaraki319‐1195Japan
| | - Takahiro Matsumoto
- Research Institute of ElectronicsShizuoka UniversityHamamatsu432‐8011Japan
- Graduate School of Medical SciencesNagoya City UniversityNagoya467‐8601Japan
- Graduate School of Design and ArchitectureNagoya City UniversityNagoya464‐0083Japan
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UVC-Based Air Disinfection Systems for Rapid Inactivation of SARS-CoV-2 Present in the Air. Pathogens 2023; 12:pathogens12030419. [PMID: 36986341 PMCID: PMC10053150 DOI: 10.3390/pathogens12030419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 12/24/2022] [Accepted: 12/28/2022] [Indexed: 03/09/2023] Open
Abstract
The World Health Organization (WHO) declared in May 2021 that SARS-CoV-2 is transmitted not only by close contact with infectious respiratory fluids from infected people or contaminated materials but also indirectly through air. Airborne transmission has serious implications for the control measures we can deploy, given the emergence of more transmissible variants. This emphasizes the need to deploy a mechanism to reduce the viral load in the air, especially in closed and crowded places such as hospitals, public transport buses, etc. In this study, we explored ultraviolet C (UVC) radiation for its ability to inactivate the SARS-CoV-2 particles present in aerosols and designed an air disinfection system to eliminate infectious viruses. We studied the virus inactivation kinetics to identify the UVC dosage required to achieve maximum virus inactivation. Based on the experimental data, UVC-based devices were designed for the sanitization of air through HVAC systems in closed spaces. Further, a risk assessment model to estimate the risk reduction was applied which showed that the use of UVC radiation could result in the reduction of the risk of infection in occupied spaces by up to 90%.
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35
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Duncan MA, Welch D, Shuryak I, Brenner DJ. Ocular and Facial Far-UVC Doses from Ceiling-Mounted 222 nm Far-UVC Fixtures. Photochem Photobiol 2023; 99:160-167. [PMID: 35818780 PMCID: PMC10087841 DOI: 10.1111/php.13671] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/08/2022] [Indexed: 01/25/2023]
Abstract
Far-UVC radiation, defined in this paper as ultraviolet (UV) radiation with wavelengths from 200 to 235 nm, is a promising tool to help prevent the spread of disease. The unique advantage of far-UVC technology over traditional UV germicidal irradiation lies in the potential for direct application of far-UVC into occupied spaces since antimicrobial doses of far-UVC are significantly below the recommended daily safe exposure limits. This study used a ceiling-mounted far-UVC fixture emitting at 222 nm to directly irradiate an indoor space and then evaluated the doses received upon a manikin. Radiation-sensitive film was affixed to the head, nose, lip and eyes of the manikin, and the 8-h equivalent exposure dose was determined. Variables examined included manikin height (sitting or standing position), manikin offset from directly below the fixture, tilt of the manikin, the addition of glasses, the addition of hair and different anatomical feature sizes. Importantly, at the manikin position with the highest dose to eyes, the average eye dose was only 5.8% of the maximum directly measured dose. These results provide the first experimental analysis of possible exposure doses a human would experience from an indoor far-UVC installation.
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Affiliation(s)
- Michael A Duncan
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
| | - David Welch
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
| | - Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
| | - David J Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY, USA
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36
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Link MF, Shore A, Hamadani BH, Poppendieck D. Ozone Generation from a Germicidal Ultraviolet Lamp with Peak Emission at 222 nm. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2023; 10:10.1021/acs.estlett.3c00318. [PMID: 38487621 PMCID: PMC10938353 DOI: 10.1021/acs.estlett.3c00318] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
Recent interest in commercial devices containing germicidal ultraviolet lamps with a peak emission wavelength at 222 nm (GUV222) has focused on mitigating virus transmission indoors while posing minimum risk to human tissue. However, 222 nm light can produce ozone (O3) in air. O3 is an undesirable component of indoor air because of health impacts from acute to chronic exposure and its ability to degrade indoor air quality through oxidation chemistry. In seven four-hour experiments we measured O3 produced from a single filtered GUV222 lamp in a 31.5 m3 stainless steel chamber. Using an emission model, we determined an O3 generation rate of 19.4 ppbv h-1 ± 0.3 ppbv h-1 (equivalent to 1.22 mg h-1 ± 0.02 mg h-1). We estimated the fluence rate from the lamp using two methods: (1) chemical actinometry using tetrachloroethylene (actinometry) and (2) geometric projection of the irradiance field from radial and angular distribution measurements of the GUV222 lamp fluence (irradiance). Using the estimated lamp fluence rates of 2.2 μW cm-2 (actinometry) and 3.2 μW cm-2 (irradiance) we predicted O3 production in our chamber within 20 % of the average measured mixing ratio. Future studies should evaluate the indoor air quality impacts of GUV222 technologies.
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Affiliation(s)
- Michael F. Link
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Andrew Shore
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Behrang H. Hamadani
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Dustin Poppendieck
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
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Welch D, Kleiman NJ, Arden PC, Kuryla CL, Buonanno M, Ponnaiya B, Wu X, Brenner DJ. No Evidence of Induced Skin Cancer or Other Skin Abnormalities after Long-Term (66 week) Chronic Exposure to 222-nm Far-UVC Radiation. Photochem Photobiol 2023; 99:168-175. [PMID: 35614842 PMCID: PMC9691791 DOI: 10.1111/php.13656] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/23/2022] [Indexed: 01/25/2023]
Abstract
Far-UVC radiation, typically defined as 200-235 nm, has similar or greater anti-microbial efficacy compared with conventional 254-nm germicidal radiation. In addition, biophysical considerations of the interaction of far-UVC with tissue, as well as multiple short-term safety studies in animal models and humans, suggest that far-UVC exposure may be safe for skin and eye tissue. Nevertheless, the potential for skin cancer after chronic long-term exposure to far-UVC has not been studied. Here, we assessed far-UVC induced carcinogenic skin changes and other pathological dermal abnormalities in 96 SKH-1 hairless mice of both sexes that were exposed to average daily dorsal skin doses of 400, 130 or 55 mJ cm-2 of 222 nm far-UVC radiation for 66 weeks, 5 days per week, 8 h per day, as well as similarly-treated unexposed controls. No evidence for increased skin cancer, abnormal skin growths or incidental skin pathology findings was observed in the far-UVC-exposed mice. In addition, there were no significant changes in morbidity or mortality. The findings from this study support the long-term safety of long-term chronic exposure to far-UVC radiation, and therefore its potential suitability as a practical anti-microbial approach to reduce airborne viral and bacterial loads in occupied indoor settings.
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Affiliation(s)
- David Welch
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY,Corresponding author: (David Welch)
| | - Norman J. Kleiman
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Irving Medical Center, New York, NY
| | - Peter C. Arden
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Irving Medical Center, New York, NY
| | - Christine L. Kuryla
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Irving Medical Center, New York, NY
| | - Manuela Buonanno
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY
| | - Brian Ponnaiya
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY
| | - Xuefeng Wu
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY
| | - David J. Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, NY
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Biffi S, Signorini L, Cattaneo L, Della Corna L, Guercilena A, D'Alessandro S, Ferrante P, Delbue S. Determination of the UV Inactivation Constant Under 280 nm UV LED Irradiation for SARS-CoV-2. Photochem Photobiol 2023; 99:101-105. [PMID: 35578782 PMCID: PMC9347497 DOI: 10.1111/php.13653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 05/14/2022] [Indexed: 01/25/2023]
Abstract
The ongoing emergency provoked by the SARS-CoV-2 pandemic demands the development of technologies to mitigate the spread of infection, and UV irradiation is a technique that can efficiently address this issue. However, proper use of UV equipment for disinfection requires an understanding of how the effects on SARS-CoV-2 are dependent on certain parameters. In this work, we determined the UV-C inactivation constant k for SARS-CoV-2 using an LED source at λ = 280 nm. Specifically, a Log3 reduction was measured after irradiation for 24 min with a delivered UV-C dose of 23 J m-2 . By multitarget model fitting, n = 2 and k = 0.32 ± 0.02 m2 J-1 were obtained. A lag time for the inactivation effect was also observed, which was attributed to the low irradiation levels used to perform the study. The combination of k and delay time allows for reliable estimation of disinfection times in small, closed environments.
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Affiliation(s)
- Silvia Biffi
- Light and Colour Engineering s.r.l, Piazza Della Repubblica, Mediglia, Italy
| | - Lucia Signorini
- Laboratory of Molecular Virology, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Luciano Cattaneo
- Light and Colour Engineering s.r.l, Piazza Della Repubblica, Mediglia, Italy
| | | | | | - Sarah D'Alessandro
- Laboratory of Molecular Virology, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Pasquale Ferrante
- Laboratory of Molecular Virology, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Serena Delbue
- Laboratory of Molecular Virology, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
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Parsa SM. Mega-scale desalination Efficacy (Reverse Osmosis, Electrodialysis, Membrane Distillation, MED, MSF) during COVID-19: Evidence from salinity, pretreatment methods, temperature of operation. JOURNAL OF HAZARDOUS MATERIALS ADVANCES 2022:100217. [PMID: 37521749 PMCID: PMC9744688 DOI: 10.1016/j.hazadv.2022.100217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The unprecedented situation of the COVID-19 pandemic heavily polluted water bodies whereas the presence of SARS-CoV-2, even in treated wastewater in every corner of the world is reported. The main aim of the present study is to show the effectiveness and feasibility of some well-known desalination technologies which are reverse osmosis (RO), Electrodialysis (ED), Membrane Distillation (MD), multi effect distillation (MED), and multi stage flashing (MSF) during the COVID-19 pandemic. Systems’ effectiveness against the novel coronavirus based on three parameters of nasopharynx/nasal saline-irrigation, temperature of operation and pretreatment methods are evaluated. First, based on previous clinical studies, it showed that using saline solution (hypertonic saline >0.9% concentration) for gargling/irrigating of nasal/nasopharynx/throat results in reducing and replication of the viral in patients, subsequently the feed water of desalination plants which has concentration higher than 3.5% (35000ppm) is preventive against the SARS-CoV-2 virus. Second, the temperature operation of thermally-driven desalination; MSF and MED (70-120°C) and MD (55-85°C) is high enough to inhibit the contamination of plant structure and viral survival in feed water. The third factor is utilizing various pretreatment process such as chlorination, filtration, thermal/precipitation softening, ultrafiltration (mostly for RO, but also for MD, MED and MSF), which are powerful treatment methods against biologically-contaminated feed water particularly the SARS-CoV-2. Eventually, it can be concluded that large-scale desalination plants during COVID-19 and similar situation are completely reliable for providing safe drinking water.
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Contributions of vibrational spectroscopy to virology: A review. CLINICAL SPECTROSCOPY 2022; 4:100022. [PMCID: PMC9093054 DOI: 10.1016/j.clispe.2022.100022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/30/2022] [Accepted: 05/04/2022] [Indexed: 06/17/2023]
Abstract
Vibrational spectroscopic techniques, both infrared absorption and Raman scattering, are high precision, label free analytical techniques which have found applications in fields as diverse as analytical chemistry, pharmacology, forensics and archeometrics and, in recent times, have attracted increasing attention for biomedical applications. As analytical techniques, they have been applied to the characterisation of viruses as early as the 1970 s, and, in the context of the coronavirus disease 2019 (COVID-19) pandemic, have been explored in response to the World Health Organisation as novel methodologies to aid in the global efforts to implement and improve rapid screening of viral infection. This review considers the history of the application of vibrational spectroscopic techniques to the characterisation of the morphology and chemical compositions of viruses, their attachment to, uptake by and replication in cells, and their potential for the detection of viruses in population screening, and in infection response monitoring applications. Particular consideration is devoted to recent efforts in the detection of severe acute respiratory syndrome coronavirus 2, and monitoring COVID-19.
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41
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Matsuura R, Lo CW, Ogawa T, Nakagawa M, Takei M, Matsumoto Y, Wada S, Aida Y. Comparison of the inactivation capacity of various UV wavelengths on SARS-CoV-2. Biochem Biophys Rep 2022; 32:101379. [PMCID: PMC9638801 DOI: 10.1016/j.bbrep.2022.101379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/05/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a worldwide pandemic. Ultraviolet (UV) is regarded as a very powerful tool against SARS-CoV-2. However, the inactivating effects of different UV wavelengths on SARS-CoV-2 under the same conditions have hardly been compared. Here, we showed that SARS-CoV-2 cultured in Dulbecco's modified Eagle's medium and 2% fetal bovine serum was efficiently inactivated by irradiation with 222, 254, and 265 wavelengths UV, but not at 308 nm. In addition, it was revealed that UV absorption by DMEM-2% FBS is very efficient at 222 nm. Our results present potentially important information for selecting the optimum UV wavelength according to the application.
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Affiliation(s)
- Ryosuke Matsuura
- Laboratory of Global Infectious Diseases Control Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamichou, Itabashi-ku, Tokyo, 173-8610, Japan
| | - Chieh-Wen Lo
- Laboratory of Global Infectious Diseases Control Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamichou, Itabashi-ku, Tokyo, 173-8610, Japan
- Laboratory of Global Animal Resource Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Takayo Ogawa
- Photonics Control Technology Team, RIKEN Center for Advanced Photonics, Hirosawa 2-1, Wako, 351-0198, Japan
| | - Masaru Nakagawa
- Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamichou, Itabashi-ku, Tokyo, 173-8610, Japan
| | - Masami Takei
- Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamichou, Itabashi-ku, Tokyo, 173-8610, Japan
| | - Yasunobu Matsumoto
- Laboratory of Global Infectious Diseases Control Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Laboratory of Global Animal Resource Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Satoshi Wada
- Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamichou, Itabashi-ku, Tokyo, 173-8610, Japan
- Photonics Control Technology Team, RIKEN Center for Advanced Photonics, Hirosawa 2-1, Wako, 351-0198, Japan
| | - Yoko Aida
- Laboratory of Global Infectious Diseases Control Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamichou, Itabashi-ku, Tokyo, 173-8610, Japan
- Laboratory of Global Animal Resource Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Corresponding author. Laboratory of Global Infectious Diseases Control Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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42
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Ultrafast inactivation of SARS-CoV-2 with 266 nm lasers. Sci Rep 2022; 12:18640. [PMID: 36333440 PMCID: PMC9636154 DOI: 10.1038/s41598-022-23423-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Disinfection eliminates pathogenic microorganisms and ensures a biosafe environment for human beings. The rapid spread of COVID-19 is challenging traditional disinfection methods in terms of reducing harmful side effects and conducting faster processes. Spraying large-scale chemical disinfectants is harmful to individuals and the environment, while UV lamp and light-emitting diode (LED) disinfection still requires a long exposure time due to the low irradiance and highly divergent beam characteristics. Given that a laser maintains a high irradiance over a long distance, we studied the effectiveness of lasers as a new disinfection method, and the results show the capability for ultrafast inactivation of SARS-CoV-2 virus with a 266 nm laser. This work confirms UV lasers as a good candidate for disinfection.
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43
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McLeod RS, Hopfe CJ, Bodenschatz E, Moriske H, Pöschl U, Salthammer T, Curtius J, Helleis F, Niessner J, Herr C, Klimach T, Seipp M, Steffens T, Witt C, Willich SN. A multi-layered strategy for COVID-19 infection prophylaxis in schools: A review of the evidence for masks, distancing, and ventilation. INDOOR AIR 2022; 32:e13142. [PMID: 36305077 PMCID: PMC9827916 DOI: 10.1111/ina.13142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/05/2022]
Abstract
Implications for the academic and interpersonal development of children and adolescents underpin a global political consensus to maintain in-classroom teaching during the ongoing COVID-19 pandemic. In support of this aim, the WHO and UNICEF have called for schools around the globe to be made safer from the risk of COVID-19 transmission. Detailed guidance is needed on how this goal can be successfully implemented in a wide variety of educational settings in order to effectively mitigate impacts on the health of students, staff, their families, and society. This review provides a comprehensive synthesis of current scientific evidence and emerging standards in relation to the use of layered prevention strategies (involving masks, distancing, and ventilation), setting out the basis for their implementation in the school environment. In the presence of increasingly infectious SARS-Cov-2 variants, in-classroom teaching can only be safely maintained through a layered strategy combining multiple protective measures. The precise measures that are needed at any point in time depend upon a number of dynamic factors, including the specific threat-level posed by the circulating variant, the level of community infection, and the political acceptability of the resultant risk. By consistently implementing appropriate prophylaxis measures, evidence shows that the risk of infection from in-classroom teaching can be dramatically reduced. Current studies indicate that wearing high-quality masks and regular testing are amongst the most important measures in preventing infection transmission; whilst effective natural and mechanical ventilation systems have been shown to reduce infection risks in classrooms by over 80%.
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Affiliation(s)
- Robert S. McLeod
- Institute for Building Physics, Services and ConstructionGraz University of TechnologyGrazAustria
| | - Christina J. Hopfe
- Institute for Building Physics, Services and ConstructionGraz University of TechnologyGrazAustria
| | - Eberhard Bodenschatz
- Max Planck Institute for Dynamics and Self‐OrganizationGottingenGermany
- Georg‐August‐University GöttingenGottingenGermany
| | | | - Ulrich Pöschl
- Max Planck Institute for ChemistryMainzGermany
- Johannes Gutenberg University MainzMainzGermany
| | | | | | | | | | | | | | - Martin Seipp
- Technical University of Central HesseGiessenGermany
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44
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Enaki NA, Paslari T, Bazgan S, Starodub E, Munteanu I, Turcan M, Eremeev V, Profir A, Mihailescu IN. UVC radiation intensity dependence of pathogen decontamination rate: semiclassical theory and experiment. EUROPEAN PHYSICAL JOURNAL PLUS 2022; 137:1047. [PMID: 36123970 PMCID: PMC9476412 DOI: 10.1140/epjp/s13360-022-03252-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
A semiclassical (light classical and molecule quantum) model describing the dependence of DNA/RNA dimerization rate as function of the ultraviolet C (UVC) radiation's intensity is proposed. Particularly, a nonlinear model is developed based on the Raman-like processes in quantum optics. The main result of the theory shows that the process of dimerization in the DNA/RNA depends strongly on the UVC light's intensity, thus proving a possible quantum microscopical mechanism of the interaction of UV light with the DNA. To corroborate the theoretical findings, we realize some experiments, by which want to investigate how the inactivation rate of the yeast colonies depends on the intensity of the UVC irradiation. The experimental results evidence a nonlinear decreasing of the residual yeast colonies as a function of the intensity in the irradiation process. The possibilities to optimize the intensity of UVC radiation in the considered decontamination equipment by using metamaterials are studied. The application of such equipment in disinfection of fluids (air, water, droplets, etc.), as well for the SARS-CoV-2-infected aerosols, is discussed.
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Affiliation(s)
- Nicolae A. Enaki
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
| | - Tatiana Paslari
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
| | - Sergiu Bazgan
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
| | - Elena Starodub
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
| | - Ion Munteanu
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
| | - Marina Turcan
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
| | - Vitalie Eremeev
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
- Instituto de Ciencias Básicas, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
| | - Aurelia Profir
- Quantum Optics and Kinetic Processes Lab of Institute of Applied Physics of Moldova, Chisinau, MD 2028 Republic of Moldova
- Moldova State University Department of Computer Science, 60 Alexei Mateevici str., Chisinau, MD-2009 Republic of Moldova
| | - Ion N. Mihailescu
- National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG 36, 77125 Bucharest-Magurele, Romania
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45
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Henderson J, Ma B, Cohen M, Dazey J, Meschke JS, Linden KG. Field study of early implementation of UV sources and their relative effectiveness for public health and safety. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2022; 19:524-537. [PMID: 35816423 DOI: 10.1080/15459624.2022.2100404] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The emergence of COVID-19 and its corresponding public health burden has prompted industries to rapidly implement traditional and novel control strategies to mitigate the likelihood of SARS-CoV-2 transmission, generating a surge of interest and application of ultraviolet germicidal irradiation (UVGI) sources as disinfection systems. With this increased attention the need to evaluate the efficacy and safety of these types of devices is paramount. A field study of the early implementation of UVGI devices was conducted at the Space Needle located in Seattle, Washington. Six devices were evaluated, including four low-pressure (LP) mercury-vapor lamp devices for air and surface sanitation not designed for human exposure and two krypton chloride (KrCl*) excimer lamp devices to be operated on and around humans. Emission spectra and ultraviolet (UV) irradiance at different locations from the UV devices were measured and germicidal effectiveness against SARS-CoV-2 was estimated. The human safety of KrCl* excimer devices was also evaluated based on measured irradiance and estimated exposure durations. Our results show all LP devices emitted UV radiation primarily at 254 nm as expected. Both KrCl* excimers emitted far UVC irradiation at 222 nm as advertised but also emitted at longer, more hazardous wavelengths (228 to 262 nm). All LP devices emitted strong UVC irradiance, which was estimated to achieve three log reduction of SARS-CoV-2 within 10 sec of exposure at reasonable working distances. KrCl* excimers, however, emitted much lower irradiance than needed for effective disinfection of SARS-CoV-2 (>90% inactivation) within the typical exposure times. UV fluence from KrCl* excimer devices for employees was below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) under the reported device usage and work shifts. However, photosensitive individuals, human susceptibility, or exposure to multiple UV sources throughout a worker's day, were not accounted for in this study. Caution should be used when determining the acceptability of UV exposure to workers in this occupational setting and future work should focus on UVGI sources in public settings.
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Affiliation(s)
- Jennifer Henderson
- Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Ben Ma
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado
| | - Martin Cohen
- Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, Washington
| | | | - John Scott Meschke
- Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado
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46
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Ruetalo N, Berger S, Niessner J, Schindler M. Inactivation of aerosolized SARS-CoV-2 by 254 nm UV-C irradiation. INDOOR AIR 2022; 32:e13115. [PMID: 36168221 PMCID: PMC9538331 DOI: 10.1111/ina.13115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 06/12/2023]
Abstract
Surface residing SARS-CoV-2 is efficiently inactivated by UV-C irradiation. This raises the question whether UV-C-based technologies are also suitable to decontaminate SARS-CoV-2- containing aerosols and which doses are needed to achieve inactivation. Here, we designed a test bench to generate aerosolized SARS-CoV-2 and exposed the aerosols to a defined UV-C dose. Our results demonstrate that the exposure of aerosolized SARS-CoV-2 with a low average dose in the order of 0.42-0.51 mJ/cm2 UV-C at 254 nm resulted in more than 99.9% reduction in viral titers. Altogether, UV-C-based decontamination of aerosols seems highly effective to achieve a significant reduction in SARS-CoV-2 infectivity.
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Affiliation(s)
- Natalia Ruetalo
- Institute for Medical Virology and Epidemiology of Viral DiseasesUniversity Hospital TübingenTübingenGermany
| | - Simon Berger
- Institute for Flow in Additively Manufactured Porous MediaHochschule HeilbronnHeilbronnGermany
| | - Jennifer Niessner
- Institute for Flow in Additively Manufactured Porous MediaHochschule HeilbronnHeilbronnGermany
| | - Michael Schindler
- Institute for Medical Virology and Epidemiology of Viral DiseasesUniversity Hospital TübingenTübingenGermany
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47
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Robinson RT, Mahfooz N, Rosas-Mejia O, Liu Y, Hull NM. UV 222 disinfection of SARS-CoV-2 in solution. Sci Rep 2022; 12:14545. [PMID: 36008435 PMCID: PMC9406255 DOI: 10.1038/s41598-022-18385-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 08/10/2022] [Indexed: 11/29/2022] Open
Abstract
There is an urgent need for evidence-based engineering controls to reduce transmission of SARS-CoV-2, which causes COVID-19. Although ultraviolet (UV) light is known to inactivate coronaviruses, conventional UV lamps contain toxic mercury and emit wavelengths (254 nm) that are more hazardous to humans than krypton chlorine excimer lamps emitting 222 nm (UV222). Here we used culture and molecular assays to provide the first dose response for SARS-CoV-2 solution exposed to UV222. Culture assays (plaque infectivity to Vero host) demonstrated more than 99.99% disinfection of SARS-CoV-2 after a UV222 dose of 8 mJ/cm2 (pseudo-first order rate constant = 0.64 cm2/mJ). Immediately after UV222 treatment, RT-qPCR assays targeting the nucleocapsid (N) gene demonstrated ~ 10% contribution of N gene damage to disinfection kinetics, and an ELISA assay targeting the N protein demonstrated no contribution of N protein damage to disinfection kinetics. Molecular results suggest other gene and protein damage contributed more to disinfection. After 3 days incubation with host cells, RT-qPCR and ELISA kinetics of UV222 treated SARS-CoV-2 were similar to culture kinetics, suggesting validity of using molecular assays to measure UV disinfection without culture. These data provide quantitative disinfection kinetics which can inform implementation of UV222 for preventing transmission of COVID-19.
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Affiliation(s)
- Richard T Robinson
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
- Infectious Diseases Institute, The Ohio State University, Columbus, OH, USA
| | - Najmus Mahfooz
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
| | - Oscar Rosas-Mejia
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA
| | - Yijing Liu
- Department of Civil, Environmental, and Geodetic Engineering, The Ohio State University, 2070 Neil Ave, Hitchcock 417C, Columbus, OH, 43210, USA
| | - Natalie M Hull
- Department of Civil, Environmental, and Geodetic Engineering, The Ohio State University, 2070 Neil Ave, Hitchcock 417C, Columbus, OH, 43210, USA.
- Sustainability Institute, The Ohio State University, Columbus, OH, USA.
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48
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Sayidmarie KH, Mohammed B, Mohammed AJ, Abbosh A. Combating Coronavirus Using Resonant Electromagnetic Irradiation. IEEE JOURNAL OF ELECTROMAGNETICS, RF AND MICROWAVES IN MEDICINE AND BIOLOGY 2022; 6:477-484. [PMID: 36514675 PMCID: PMC9728540 DOI: 10.1109/jerm.2022.3194727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 07/10/2022] [Accepted: 07/24/2022] [Indexed: 12/16/2022]
Abstract
The interaction of electromagnetic (EM) waves with the COVID-19 virus is studied to define the frequencies that cause maximum energy absorption by the virus and the power level needed to cause a lethal temperature rise. The full-wave EM simulator is used to model the virus and study the effects of its size and dielectric properties on the absorbed power across a wide range of frequencies. The results confirm potential resonance conditions, where specific frequencies produce maximum absorption and subsequent temperature rise that can destroy the virus. Furthermore, the study confirms that maximum power deposition in the virus occurs at specific wavelengths depending on its size. Also, the simulation is used to find the power required to destroy the virus and determine the total power required to destroy it in an oral activity, such as coughing, made by infected individuals. Furthermore, the study explained why irradiation by UV-C band is effective to decrease virus activity or even eradicate it.
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Affiliation(s)
| | - Beadaa Mohammed
- School of Information Technology and Electrical EngineeringThe University of Queensland Brisbane QLD 4103 Australia
| | - Asmaa J Mohammed
- College of Environmental Science and TechnologyMosul University Mosul 41001 Iraq
| | - Amin Abbosh
- School of Information Technology and Electrical EngineeringThe University of Queensland Brisbane QLD 4103 Australia
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49
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MacIsaac SA, Mullin TJ, Munoz S, Ontiveros CC, Gagnon GA. Immersive ultraviolet disinfection of E. coli and MS2 phage on woven cotton textiles. Sci Rep 2022; 12:13260. [PMID: 35918389 PMCID: PMC9345007 DOI: 10.1038/s41598-022-17663-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/28/2022] [Indexed: 12/01/2022] Open
Abstract
Immersive ultraviolet disinfection provides a chemical-free technology for safer textiles, surfaces, and public spaces by inactivating communicable pathogens. This study examined immersive UV disinfection, using a disinfection cabinet, of E. coli and MS2 that was inoculated on white cotton T-shirts. The impact that porous materials have on UV disinfection is poorly understood with the majority of previous surface disinfection research focusing on hard, smooth surfaces. Several approaches were used in this study to characterize the light dynamics within the disinfection cabinet including colorimetric dosimetry coupons, biodosimetry, and spectroradiometry. Micro and macro geometry of porous surfaces are important factors to consider when using immersive UV technologies. The geometry of the cabinet impacted the distribution of emitted UV light within the disinfection cabinet and the physical properties of a porous material, such as the woven pattern of cotton, both contribute to UV disinfection efficiency. This work identified that light distribution is crucial for immersive UV technologies as the delivered fluence was highly variable within the disinfection cabinet and resulted in a difference of several logs of reduction for adjacent areas of T-shirt samples. Other inoculated areas achieved upwards of 1-log reductions values for MS2 and upwards of 2-log reductions for E. coli.
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Affiliation(s)
- Sean A MacIsaac
- Centre for Water Resources Studies, Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, NS, B3H 4R2, Canada
| | - Toni J Mullin
- Centre for Water Resources Studies, Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, NS, B3H 4R2, Canada
| | - Sebastian Munoz
- Centre for Water Resources Studies, Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, NS, B3H 4R2, Canada
| | - C Carolina Ontiveros
- Centre for Water Resources Studies, Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, NS, B3H 4R2, Canada
| | - Graham A Gagnon
- Centre for Water Resources Studies, Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, NS, B3H 4R2, Canada.
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50
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Schuit MA, Larason TC, Krause ML, Green BM, Holland BP, Wood SP, Grantham S, Zong Y, Zarobila CJ, Freeburger DL, Miller DM, Bohannon JK, Ratnesar-Shumate SA, Blatchley ER, Li X, Dabisch PA, Miller CC. SARS-CoV-2 inactivation by ultraviolet radiation and visible light is dependent on wavelength and sample matrix. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B: BIOLOGY 2022; 233:112503. [PMID: 35779426 PMCID: PMC9221687 DOI: 10.1016/j.jphotobiol.2022.112503] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/19/2022] [Accepted: 06/18/2022] [Indexed: 11/11/2022]
Abstract
Numerous studies have demonstrated that SARS-CoV-2 can be inactivated by ultraviolet (UV) radiation. However, there are few data available on the relative efficacy of different wavelengths of UV radiation and visible light, which complicates assessments of UV decontamination interventions. The present study evaluated the effects of monochromatic radiation at 16 wavelengths from 222 nm through 488 nm on SARS-CoV-2 in liquid aliquots and dried droplets of water and simulated saliva. The data were used to generate a set of action spectra which quantify the susceptibility of SARS-CoV-2 to genome damage and inactivation across the tested wavelengths. UVC wavelengths (≤280 nm) were most effective for inactivating SARS-CoV-2, although inactivation rates were dependent on sample type. Results from this study suggest that UV radiation can effectively inactivate SARS-CoV-2 in liquids and dried droplets, and provide a foundation for understanding the factors which affect the efficacy of different wavelengths in real-world settings.
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