1
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Bajek D, Sharpe K, Eadie E. Black ceiling tiles reduce occupational ultraviolet light exposure from phototherapy cabinets. Clin Exp Dermatol 2024; 49:893-895. [PMID: 38494852 DOI: 10.1093/ced/llae102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/25/2024] [Accepted: 03/11/2024] [Indexed: 03/19/2024]
Abstract
Phototherapy clinics administer ultraviolet (UV) light to patients using phototherapy cabinets. The UV radiation from these cabinets is reflected on the white ceiling tiles of the clinic and is then redirected toward both staff and patients in the area. This is particularly problematic for clinical technologists who must undertake dosimetry in these areas and have a specific time (often as low as 30 min) before they reach their maximum exposure limit. By replacing white tiles with black ones, which absorb any stray radiation, we were able to reduce stray reflection by almost 90%, prolonging the time to maximum exposure by nearly 10 times. We present these findings to encourage other similar clinics to undertake the simple protocols outlined in this article, which will significantly improve staff and patient safety.
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Affiliation(s)
- David Bajek
- Photobiology Unit, NHS Tayside, Ninewells Hospital, Dundee, UK
- School of Medicine, University of Dundee, Dundee, UK
| | | | - Ewan Eadie
- Photobiology Unit, NHS Tayside, Ninewells Hospital, Dundee, UK
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2
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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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3
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Welch D, Hashmi R, Petersen C, Erde S, Brenner DJ, Nardell E. Film dosimetry for occupant exposure monitoring within Far-UVC installations. Photochem Photobiol 2024. [PMID: 38702942 DOI: 10.1111/php.13960] [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: 01/03/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 05/06/2024]
Abstract
Far-UVC radiation between 200 and 230 nm is a promising technology for reducing airborne disease transmission. Previous work with far-UVC lamps has demonstrated the efficacy of far-UVC radiation to inactivate bacteria and viruses while presenting minimal human health hazards. While far-UVC intentionally exposes the occupied space, effectively disinfecting air between occupants, installations must still ensure that occupant eye and skin exposure is within the recommended daily limits. This study examines far-UVC-sensitive films for measuring the dose received by occupants within two real-world far-UVC installations. The film is characterized for accuracy, angular response, wavelength response, and sources of uncertainty in film response, and used to obtain individual exposure doses that account for both the non-uniform irradiance and the unique motion of individuals within the space. Dosimetry results using the films, which account for the time-weighted average exposure of an occupant, ranged from 10% to 49% of the maximum calculated stationary dose based on peak irradiance measurements. Results from this study spotlight the need to incorporate time-weighted average considerations into the design and safety assessment of far-UVC installations to ultimately operate far-UVC technology with its full potential to prevent the spread of potentially fatal infectious diseases.
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Affiliation(s)
- David Welch
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York, USA
| | - Raabia Hashmi
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York, USA
| | - Camryn Petersen
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York, USA
| | - Steven Erde
- College of Dental Medicine, Columbia University Irving Medical Center, New York, New York, USA
| | - David J Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, New York, USA
| | - Edward Nardell
- Division of Global Health Equity, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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4
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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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7
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Zhang H, Lai ACK. Evaluation of Single-Pass Disinfection Performance of Far-UVC Light on Airborne Microorganisms in Duct Flows. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17849-17857. [PMID: 36469399 DOI: 10.1021/acs.est.2c04861] [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: 06/17/2023]
Abstract
Far-UVC irradiation (222 nm) is considered an emerging and sustainable solution for future infection and pandemic challenges. We examined the disinfection performance of a krypton-chloride lamp, with a quasi-monochromatic UVC peak at 222 nm, for inactivating airborne microorganisms in a full-scale ventilation duct system. Single-pass disinfection efficacy of far-UVC was determined and compared with that of a conventional mercury-type UVC (254 nm) lamp. Four bacteria, Escherichia coli (E. coli), Pseudomonas alcaligenes (P. alcaligenes), Serratia marcescens (S. marcescens), and Staphylococcus epidermidis (S. epidermidis), as well as bacteriophage P22, were tested under UV exposure with different velocities of duct flows. The data revealed that as the air velocity increased from 0.7 to 4 m/s, the far-UVC disinfection efficacies would decrease by 42, 47, 35, 39, and 33% for these five microorganisms, respectively. The inactivation rate constants to far-UVC light were 4.9, 7.5, 3.3, 6.3, and 3.0 cm2/mJ for aerosolized E. coli, P. alcaligenes, S. marcescens, S. epidermidis, and bacteriophage P22, respectively. Far-UVC irradiation showed a comparable disinfection ability on airborne microorganisms compared with the 254 nm UV irradiation. This first study of far-UVC in real duct applications provides a better understanding of the disinfection performance of this solution in bioaerosol inactivation. It offers a valuable database in the sizing and design of excimer lamps for novel portable air purifiers or in-duct disinfection units.
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Affiliation(s)
- Huihui Zhang
- Department of Architecture and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong00000, China
| | - Alvin C K Lai
- Department of Architecture and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong00000, China
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