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1.
Building and Environment ; : 109530, 2022.
Article in English | ScienceDirect | ID: covidwho-2003904

ABSTRACT

This study used Computational Fluid Dynamics (CFD) to investigate air disinfection for SARS-CoV-2 by the Upper-Room Germicidal Ultraviolet (UR-GUV), with focus on ceiling impact. The study includes three indoor settings, i.e., low (airport bus), medium (classroom) and high (rehearsal room) ceilings, which were ventilated with 100% clean air (CA case), 80% air-recirculation with a low filtration (LF case), and 80% air-recirculation with a high filtration (HF case). According to the results, using UR-GUV can offset the increased infection risk caused by air recirculation, with viral concentrations in near field (NF) and far field (FF) in the LF case similar to those in the CA case. In the CA case, fraction remaining (FR) was 0.48–0.73 with 25% occupancy rate (OR) and 0.49–0.91 with 45% OR in the bus, 0.41 in NF and 0.11 in FF in the classroom, and 0.18 in NF and 0.09 in FF in the rehearsal room. Obviously, UR-GUV performance in NF can be improved in a room with a high ceiling where FR has a power relationship with UV zone height. As using UR-GUV can only extend the exposure time to get infection risk of 1% (T1%) to 8 min in NF in the classroom, and 47 min in NF in the rehearsal room, it is necessary to abide by social distancing in the two rooms. In addition, T1% in FF was calculated to be 18.3 min with 25% OR and 21.4% with 45% OR in the airport bus, showing the necessity to further wear a mask.

2.
Am J Infect Control ; 50(8): 947-953, 2022 08.
Article in English | MEDLINE | ID: covidwho-2000206

ABSTRACT

BACKGROUND: Ultraviolet germicidal irradiation (UVGI) technologies have emerged as a promising adjunct to manual cleaning, however, their potential to shorten cleaning times remains unexplored. METHODS: A <10-minute disinfection procedure was developed using a robotic UVGI platform. The efficacy and time to perform the UVGI procedure in a CT scan treatment room was compared with current protocols involving manual disinfection using biocides. For each intervention, environmental samples were taken at 12 locations in the room before and after disinfection on seven distinct occasions. RESULTS: The mean UVC dose at each sample location was found to be 13.01 ± 4.36 mJ/cm2, which exceeded published UVC thresholds for achieving log reductions of many common pathogens. Significant reductions in microbial burden were measured after both UVGI (P≤.001) and manual cleaning (P≤.05) conditions, with the UVGI procedure revealing the largest effect size (r = 0.603). DISCUSSION: These results support the hypothesis that automated deployments of UVGI technology can lead to germicidal performance that is comparable with, and potentially better than, current manual cleaning practices. CONCLUSIONS: Our findings provide early evidence that the incorporation of automated UVGI procedures into cleaning workflow could reduce turnaround times in radiology, and potentially other hospital settings.


Subject(s)
Radiology , Robotics , Disinfection/methods , Hospitals , Humans , Ultraviolet Rays
3.
IEEE International Instrumentation and Measurement Technology Conference (I2MTC) ; 2021.
Article in English | Web of Science | ID: covidwho-1978392

ABSTRACT

LED lighting is becoming increasingly pervasive in many areas ranging from ambient lighting, up to applications such as microscope illumination, UV-LED curing and, UV disinfection for air, surfaces, and water. Irradiance uniformity is often a fundamental parameter for guiding the design, comparison, and optimization of the illuminator. To this end, many methods and procedures have been proposed to guide the arrangement of the LED sources, as well as to guide the design of ad-hoc lenses. Nevertheless, there are many applications in which it is important to be able to consider other aspects as well as the uniformity of the irradiance. For this purpose, we propose both a method that allows calculating the irradiance generated by the used LED sources and, performance indicators for guiding the design and comparing different optical layouts.

4.
2022 International Symposium on Medical Robotics, ISMR 2022 ; 2022.
Article in English | Scopus | ID: covidwho-1961403

ABSTRACT

The COVID-19 pandemic has demonstrated the need for a more effective and efficient disinfection approach to combat infectious diseases. Ultraviolet germicidal irradiation (UVGI) is a proven mean for disinfection and sterilization and has been integrated into handheld devices and autonomous mobile robots. Existing UVGI robots which are commonly equipped with uncovered lamps that emit intense ultraviolet radiation suffer from: inability to be used in human presence, shadowing of objects, and long disinfection time. These robots also have a high operational cost. This paper introduces a cost effective germicidal system that utilizes UVGI to disinfect pathogens, such as viruses, bacteria, and fungi, on high contact surfaces (e.g. doors and tables). This system is composed of a team of 5-DOF mobile manipulators with end-effectors that are equipped with far-UVC excimer lamps. The design of the system is discussed with emphasis on path planning, coverage planning, and scene understanding. Evaluations of the UVGI system using simulations and irradiance models are also included. Please see the project's website for videos and simulations of the robot.1 © 2022 IEEE.

5.
J Occup Environ Hyg ; : 1-14, 2022 Aug 05.
Article in English | MEDLINE | ID: covidwho-1931709

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.

6.
Biomed Phys Eng Express ; 8(5)2022 08 10.
Article in English | MEDLINE | ID: covidwho-1922162

ABSTRACT

Objective.New technologies, including robots comprising germ-killing UV lamps, are increasingly being used to decontaminate hospitals and prevent the spread of COVID-19 and other superbugs. Existing approaches for modelling the irradiance field surrounding mobile UV disinfection robots are limited by their inability to capture the physics of their bespoke geometrical configurations and do not account for reflections. The goal of this research was to extend current models to address these limitations and to subsequently verify these models using empirically collected data.Approach.Two distinct parametric models were developed to describe a multi-lamp robotic UV system and adapted to incorporate the effects of irradiance amplification from the device's reflectors. The first model was derived from electromagnetic wave theory while the second was derived from conservation of energy and diffusion methods. Both models were tuned using data from empirical testing of an existing UV robot, and then validated using an independent set of measurements from the same device.Results.For each parameter, predictions made using the conservation of energy method were found to closely approximate the empirical data, offering more accurate estimates of the 3D irradiance field than the electromagnetic wave theory model.Significance.The versatility of the proposed method ensures that it can be easily adapted to different embodiments, providing a systematic way for researchers to develop accurate numerical models of custom UV robots, which may be used to inform deployment and/or to improve the accuracy of virtual simulation.


Subject(s)
COVID-19 , Robotics , Disinfection/methods , Humans , Ultraviolet Rays
7.
AUA Academic Conference in conjunction with 5th International Conference on Strategic and Global Studies, AUA and ICSGS 2021 ; 243:105-110, 2022.
Article in English | Scopus | ID: covidwho-1919592

ABSTRACT

Communities have had to make concerns when and how schools serving students in schools and campus should re-open against temporary closure to slow the spread of COVID-19 virus. Apart from continuing COVID-19 health protocols for all students, teachers and staffs, technology support needed for air circulation disinfection in crowded and inadequately ventilated space like a classroom. This study examines the impact of using UVC tools and combine with evidence-based source control practices, whether refine indoor air quality to best minimize exposure risk to COVID-19 for staff and students. This study found airborne disinfection can be solved through UVC irradiation with measured radiation 7,31 mW/cm2 since previous published research only need 5 mW/cm2 at least one second. The recommendation from this study, government need to raise public policy for education institutions to apply ultraviolet germicidal irradiation (UVGI) chamber to cut-off virus airborne transmission by circulating and disinfect indoor air during in-class activities all day long. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

8.
Acs Photonics ; 9(5):1513-1521, 2022.
Article in English | Web of Science | ID: covidwho-1895566

ABSTRACT

The COVID-19 pandemic has generated great interest in ultraviolet (UV) disinfection, particularly for air disinfection. Although UV disinfection was discovered close to 90 years ago, only very recently has it reached the consumer market and achieved much acceptance from the public, starting in the 2000s. The current UV light source of choice has been almost exclusively a low-pressure mercury vapor discharge lamp. Today, however, with emerging deep-UV (DUV) chip-scale technologies, there has been a significant advancement, along with ever-increasing interest, in the development and deployment of disinfection systems that employ compact devices that emit in the deep-UV spectral band (200- 280 nm), including UV light-emitting diodes (LEDs) and cathodoluminescent (CL) chips. This perspective looks into competing UV technologies (including mercury lamps and excimer lamps as benchmarks) on their optical merits and demerits and discusses the emerging chip-scale technologies of DUV electroluminescent and cathodoluminescent devices, comparing them against the benchmarks and providing an overview of the challenges and prospects. The accelerating progress in chip-scale solutions for deep-UV light sources promises a bright future in UV disinfection.

9.
Light-Emitting Devices, Materials, and Applications XXVI 2022 ; 12022, 2022.
Article in English | Scopus | ID: covidwho-1891705

ABSTRACT

Ultraviolet Germicidal Irradiation (UVGI) is a proven method of disinfection for both bacterial and viral pathogens. Since the acceleration of the COVID-19 pandemic caused by SARS-CoV-2, the industry has witnessed significant technological innovation and an influx of UV-C LEDs, devices, and disinfectant enclosures. To ensure germicidal efficacy, UV-C LEDs and associated devices need accurate characterization of their optical power and irradiance. When UV-C sources are installed in enclosures and rooms, additional challenges arise that need to be evaluated to ensure germicidal efficacy is maintained. These challenges include 1) under- and over-dosing due to non-uniformity of UV-C dosage, 2) poorly understood room/chamber dynamics and reflectance, 3) shadowing, and 4) sensor, material, and source degradation. Here, we introduce a new detector portfolio that is calibrated at critical UV-C wavelengths, such as 265 nm, and enables real time UV-C Irradiance measurements at near-field and far-field. Temporal monitoring of irradiance allows for real time dosage calculation. Seasoned optical components ensure accurate detector performance and enable source output degradation monitoring. An adaptable API, network capability, and a dashboard facilitate simultaneous monitoring of multiple detectors and easy integration with existing installation infrastructure. With a proprietary cosine diffuser, these detectors include an exceptional f2 directional response making them ideal for deployment in rooms, enclosures, and HVAC systems. © COPYRIGHT SPIE. Downloading of the is permitted for personal use only.

10.
ASHRAE Journal ; 64(3):20-30, 2022.
Article in English | Scopus | ID: covidwho-1871792

ABSTRACT

The global COVID-19 pandemic has prompted widespread demand for air cleaning technologies aimed at reducing risks of airborne pathogen transmission inside buildings. The commercial landscape for air cleaning devices is complex, ranging from conventional technologies such as high-efficiency fibrous-media filters and ultraviolet germicidal irradiation (UVGI) to a wide variety of electronic air cleaning technologies such as plasma generators, hydroxyl radical generators, ionizers, photocatalytic oxidizers and others. This article demonstrates some frequently prevalent issues in electronic air cleaner performance testing and reporting and proposes a path forward to meet research needs and improve test methods that could reduce the current uncertainty about the performance of electronic air cleaning technologies. It also provides tools to support practitioners and consumers in their decision-making regarding air cleaning technologies. Copyright 2022 ASHRAE.

11.
Materials Today Sustainability ; : 100161, 2022.
Article in English | ScienceDirect | ID: covidwho-1867617

ABSTRACT

Advanced building design technology is being proposed to eliminate all pathogens, including COVID-19, inside buildings naturally before they attack the human body. Pathogens comprise viruses, fungi, molds, protozoans, and bacteria that cause deadly diseases in humans. Thus, in this research, the application of solar irradiance through an outer glazing wall of the building forming Ultraviolet Germicidal Irradiation (UVGI) derived from sunlight has been performed to eliminate all pathogens inside the buildings before the pathogens attack the human body to cause deadly disease. Based on the findings that all pathogens, including COVID-19, can be killed with short-range wavelengths of 254-280 UVGI by disrupting their nucleic acid bonds, the pathogens are forced to malfunction in their biochemical functions and eventually the pathogens are caused to die. Simply, utilization of the outer glazing wall of a building to kill pathogens by controlling the photophysical reaction shall indeed be an interesting field of science to eliminate pathogens inside the building before those pathogens penetrate the human body.

12.
Materials Today Communications ; : 103690, 2022.
Article in English | ScienceDirect | ID: covidwho-1851853

ABSTRACT

Due to the COVID19 pandemic, solutions to automate disinfection using UV-C combined with mobile robots are beginning to be explored. It has been proved that the use of these systems highly reduces the risk of contagion. However, its use in real applications is not being as rapid as it needs to be. One of the main market input barriers is the fear of degrading facilities. For this reason, it is crucial to perform a detailed study on the degradation effect of UV-C light on inert materials. This experimental study proves that, considering exposition times equivalent to several work years in hospital rooms, only the appearance of the material is affected, but not their mechanical functionalities. This relevant result could contribute to accelerate the deployment of these beneficial disinfection technologies. For that purpose, a colorimetry test, tensile strength test, and analysis of the surface microstructure were carried out. The results showed that polymers tend to turn yellow, while fabrics lose intensity depending on the color. Red is hardly affected by UV-C, but blue and green are. Thus, this study contributes to the identification of the best materials and colors to be used in rooms subjected to disinfection processes. In addition, it is shown how the surface microstructure of the materials is altered in most of the materials, but not the tensile strength of the fabrics.

13.
5th International Conference on Computing and Informatics, ICCI 2022 ; : 92-96, 2022.
Article in English | Scopus | ID: covidwho-1846105

ABSTRACT

During the Coronavirus pandemic, the world counted on conventional sanitizing products that involved unsafe toxic chemicals. Ultraviolet Germicidal Irradiation or ultraviolet disinfection is introduced in many sanitizing applications, as it splits the DNA/RNA, forcing microorganisms unable to spread. For that, ultraviolet disinfection technology is presented in this project to replace the old nonenvironmental practices. Far-ultraviolet type C is a small part of the ultraviolet spectrum, with wavelengths from 207 nm to 222 nm proven effective against micrograms. This project aims to apply far-ultraviolet technology to design an easily used, reliable, and optimized system to control and monitor the sanitizing operation. Moreover, this project design combines two different sanitizing modes intended to serve the need of a dental clinic's daily sanitizing technique. The first mode is intended to sanitize the dentist's tools connected to a monitoring system that shows the ultraviolet type C intensity and the received dosage. The second mode is for the surfaces and handlers in the clinic;the sanitizing handheld will be attached to a distance identification system that guides the user to apply the sanitizing operation at the proper distance. Furthermore, this project will determine the disinfection parameters (dosage, intensity, exposure time, wavelength, and distance) according to the used far-ultraviolet source and the prototype design. © 2022 IEEE.

14.
ASHRAE Journal ; 63(8):26-30, 2021.
Article in English | Scopus | ID: covidwho-1801670

ABSTRACT

Ultraviolet germicidal irradiation (UVGI) of air is a proven technique for controlling infectious aerosols.1 This column summarizes an evaluation of in-duct UVGI proposals for several buildings under the control of one owner and operator with the purpose of reducing COVID-19 transmission. The column also briefly discusses upper-room UVGI. © 2021 Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc.. All rights reserved.

15.
J. Res. Natl. Inst. Stand. Technol. ; 126:29, 2022.
Article in English | Web of Science | ID: covidwho-1791942

ABSTRACT

Data for interpreting virus inactivation on N95 face filtering respirators (FFRs) by ultraviolet (UV) radiation are important in developing UV strategies for N95 FFR disinfection and reuse for any situation, whether it be everyday practices, contingency planning for expected shortages, or crisis planning for known shortages. Data regarding the integrity, form, fit, and function of N95 FFR materials following UV radiation exposure are equally important. This article provides these data for N95 FFRs following UV-C irradiation (200 nm to 280 nm) in a commercial UV-C enclosure. Viral inactivation was determined by examining the inactivation of OC43, a betacoronavirus, inoculated on N95 FFRs. Different metrological approaches were used to examine irradiated N95 FFRs to determine if there were any discernible physical differences between non-irradiated N95 FFRs and those irradiated using the UV-C enclosure. Material integrity was examined using high-resolution scanning electron microscopy. Form, fit, and function were examined using flow resistance, tensile strength, and particle filtration measurements. A separate examination of filter efficiency, fit, and strap tensile stress measurements was performed by the National Personal Protective Technology Laboratory. Data from these metrological examinations provide evidence that N95 FFR disinfection and reuse using the UV-C enclosure can be effective.

16.
Journal of Research of the National Institute of Standards and Technology ; 126:24, 2022.
Article in English | Web of Science | ID: covidwho-1761098

ABSTRACT

A method is described for inactivation of pathogens, especially airborne pathogens, using ultraviolet (UV) radiation emitted directly into occupied spaces and exposing occupants to a dose below the accepted actinic exposure limit (EL). This method is referred to as direct irradiation below exposure limits, or DIBEL. It is demonstrated herein that low-intensity UV radiation below exposure limits can achieve high levels of equivalent air changes per hour (ACH(eq)) and can be an effective component of efforts to combat airborne pathogens such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). An ACH(eq) of 4 h(-1) is presently achievable over a continuous 8 h period for the SARS-CoV-2 virus with UV-C light-emitting diodes (LEDs) having peak wavelength at 275 nm, and future improvements in LED technology and optics are anticipated to enable improvements up to 150 h(-)(1) in the coming decade. For example, the actinic EL is 60 J/m(2) at 254 nm, and human coronaviruses, including SARS-CoV-2, have a UV dose required for 90 % inactivation of about 5 J/m(2) at 254 nm. Irradiation by 254 nm UV-C at the EL is expected to provide 90 % inactivation of these organisms in air in about 40 min when the UV-C is delivered at a constant irradiance over 8 h, or in about 5 min if the UV-C is delivered at a constant irradiance over 1 h. Since the irradiation is continuous, the inactivation of initial contaminants accumulates to 99 % and then 99.9 %, and it also immediately begins inactivating any newly introduced (e.g., exhaled) pathogens at the same rate throughout the 8 h period. The efficacy for inactivating airborne pathogens with DIBEL may be expressed in terms of ACH(eq), which may be compared with conventional ventilation-based methods for air disinfection. DIBEL may be applied in addition to other disinfection methods, such as upper room UV germicidal irradiation, and mechanical ventilation and filtration. The ACH(eq) of the separate methods is additive, providing enhanced cumulative disinfection rates. Conventional air disinfection technologies have typical ACH(eq) values of about h(-1) to 5 h(-1) and maximum practical values of about 20 h(-1). UV-C DIBEL currently provides ACH(eq) values that are typically about 1 h(-1) to 10 h(-)(1), thus either complementing, or potentially substituting for, conventional technologies. UV-C DIBEL protocols are forecast herein to evolve to >100 ACH(eq) in a few years, potentially surpassing conventional technologies. UV-A (315 nm to 400 nm) and/or UV-C (100 nm to 280 nm) DIBEL is also efficacious at inactivating pathogens on surfaces. The relatively simple installation, low acquisition and operating costs, and unobtrusive aesthetic of DIBEL using UV LEDs contribute value in a layered, multi-agent disinfection strategy.

17.
AMB Express ; 12(1): 30, 2022 Mar 04.
Article in English | MEDLINE | ID: covidwho-1724548

ABSTRACT

Inanimate objects/surfaces become fomites upon contacting infectious agents such as disease-causing bacteria, fungi and viruses. Smartphones are one of the most prominent among these fomites. COVID-19 pandemic has raised the awareness on mobile sanitization, as an active measure to curb fomite-mediated viral transmission. Available mobile sanitizers and ultraviolet (UV) ray mediated mobile sanitization have their own sets of pros and cons, often being less user-friendly. This study explored the germicidal efficacy of an herbal-based sanitizer, Germi-X spray, on hands and mobiles, through microbiological techniques of micro-broth dilution and Kirby-Bauer disc diffusion assay, thumb print assay and swab test. Notably, Germi-X spray was found to be 6-67% more effective against surface pathogens, like, Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas fluorescens and Pseudomonas aeruginosa, as compared to a very popular product in the Indian market, which was taken as a control for this study. The observed anti-bacterial activity of the spray from disc-diffusion assay suggests its greater surface retentivity as compared to the control. Germicidal potency of Germi-X spray, when used to sanitize hands, was found to be greater than 80%. There was ~ 17-fold reduction in microbial counts after sanitizing smartphones with Germi-X spray. The novelty of this study lies in providing experimental evidence for this herbal-based surface sanitizer in efficiently disinfecting one of the super contaminated fomite, the smartphones. In conclusion, having an herbal base with a high germicidal efficacy against surface pathogens, together with longer surface retention, Germi-X spray appears to be an eco-friendly and cost-effective sanitizer for the surfaces of electronic gadgets like smartphones.

18.
2021 IEEE International Conference on Systems, Man, and Cybernetics, SMC 2021 ; : 3056-3060, 2021.
Article in English | Scopus | ID: covidwho-1703663

ABSTRACT

The use of ultraviolet germicidal irradiation (UVGI) technology as a means of disinfecting hospitals and other frontline settings has increased significantly in the wake of the COVID-19 pandemic. Although the science of UVGI is well established, it can be difficult to determine in practice if sufficient levels of UVC has been irradiated to kill the target microbes in a room. This research presents the development of a low-cost wireless UVC sensor that can be used to systematically track the UV irradiation dose on target surfaces during a UV disinfection procedure. We present key elements of the design of this device, which included a custom PCB, enclosure, operating software, and graphical user interface. The applicability of the system was assessed through an experiment where the devices were placed at 12 locations in a CT scan treatment room that was subject to a UVGI disinfection procedure using an autonomous UV robot. Over the course of three cleaning sessions, each lasting approximately 10 minutes, it was found that each site location received an average UVC dose of 13mJ/cm2, which is more than published D90 values for SARS-Cov-2, influenza, and a number of known pathogens that are commonly found in hospital settings. This study provides early validation of the potential effectiveness of low-power wireless UV level monitoring technology, which may form part of future distributed room sensing networks or as part of smart wearable devices carried by relevant hospital staff. © 2021 IEEE.

19.
Front Public Health ; 9: 825468, 2021.
Article in English | MEDLINE | ID: covidwho-1686580

ABSTRACT

In the pandemic of COVID-19, it is crucial to consider the hygiene of the edible and nonedible things as it could be dangerous for our health to consume infected things. Furthermore, everything cannot be boiled before eating as it can destroy fruits and essential minerals and proteins. So, there is a dire need for a smart device that could sanitize edible items. The Germicidal Ultraviolet C (UVC) has proved the capabilities of destroying viruses and pathogens found on the surface of any objects. Although, a few minutes exposure to the UVC can destroy or inactivate the viruses and the pathogens, few doses of UVC light may damage the proteins of edible items and can affect the fruits and vegetables. To this end, we have proposed a novel design of a device that is employed with Artificial Intelligence along with UVC to auto detect the edible items and act accordingly. This causes limited UVC doses to be applied on different items as detected by proposed model according to their permissible limit. Additionally, the device is employed with a smart architecture which leads to consistent distribution of UVC light on the complete surface of the edible items. This results in saving the health as well as nutrition of edible items.


Subject(s)
COVID-19 , Disinfection , Artificial Intelligence , Humans , SARS-CoV-2 , Ultraviolet Rays/adverse effects
20.
Safety and Health at Work ; 13:S116, 2022.
Article in English | EMBASE | ID: covidwho-1677004

ABSTRACT

Introduction: Filtering facepiece respirators (FFRs) reuse practices to address shortages during the COVID-19 pandemic received attention;however, evidence of SARS-CoV-2 inactivation on respirators is limited. Quality FFRs for use during outbreaks remains a priority to protect frontline and essential workers. This study aimed to compare the effectiveness of three relatively inexpensive methods to inactivate SARS-CoV-2 and ensuring respirator performance. Methods: Seven FFRs inoculated with SARS-CoV-2 were decontaminated with moist heat incubation (MHI), vapourised hydrogen peroxide (VHP), and ultraviolet germicidal irradiation (UVGI). G.stearothermophilus bioindicator was used as a control. FFR integrity, efficiency and user fit were assessed on 27 participants for 30 decontamination cycles. Ethical clearance was acquired from the University of the Witwatersrand (M200684). Results: Most participants failed fit testing for KN95 irrespective of method used except for two individuals. Participants completed more cycles after UVGI compared to VHP decontamination. Only KN95 failed filtration post-MHI, VHP and UVGI treatment. A ≥ 3 log reduction of SARS-CoV-2 was achieved using UVGI for worn FFRs (Greenline 5200 FFP2 and Makrite 9500 N95 using MHI;3M 8810SSA FFP2 using VHP;Greenline 5200 FFP2). UVGI and VHP methods achieved a 6 log reduction of G.stearothermophilus. Conclusion: Some FFRs could withstand 30 cycles of UVGI and VHP processing without diminishing filtration efficiency or fit. SARS-CoV-2 log reduction varied across the methods and FFRs models emphasing the importance of validation before reuse during a crisis.

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