Journal articles: 'UVGI'

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Green, Christopher F., Pasquale V. Scarpino, Paul Jensen, Nancy J. Jensen, and Shawn G. Gibbs. "Disinfection of selected Aspergillus spp. using ultraviolet germicidal irradiation." Canadian Journal of Microbiology 50, no. 3 (March 1, 2004): 221–24. http://dx.doi.org/10.1139/w04-002.

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Aims: The efficacy of ultraviolet germicidal irradiation (UVGI) and the UVGI dose necessary to inactivate fungal spores on an agar surface for cultures of Aspergillus flavus and Aspergillus fumigatus were determined. Methods and results: A four-chambered UVGI testing unit with a 9-W, Phillips, low pressure, mercury UVGI lamp in each chamber was used in this study. An aperture was adjusted to provide 50, 100, 150, and 200 µW/cm2 of uniform flux to the surfaces of the Petri dish, resulting in a total UVGI dose to the surface of the Petri dishes ranging from 12 to 96 mJ/cm2. The UVGI dose necessary to inactivate 90% of the A. flavus and A. fumigatus was 35 and 54 mJ/cm2, respectively. Conclusions: UVGI can be used to inactivate culturable fungal spores. Aspergillus flavus was more susceptible than A. fumigatus to UVGI. Significance and impact of the study: These results may not be directly correlated to the effect of UVGI on airborne fungal spores, but they indicate that current technology may not be efficacious as a supplement to ventilation unless it can provide higher doses of UVGI to kill spores traveling through the irradiated zone.Key words: Aspergillus, ultraviolet germicidal irradiation, fungi.

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Green, Christopher F., Craig S. Davidson, Pasquale V. Scarpino, and Shawn G. Gibbs. "Ultraviolet germicidal irradiation disinfection of Stachybotrys chartarum." Canadian Journal of Microbiology 51, no. 9 (September 1, 2005): 801–4. http://dx.doi.org/10.1139/w05-061.

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The ultraviolet germicidal irradiation (UVGI) dose necessary to inactivate fungal spores on an agar surface and the efficacy of UVGI were determined for cultures of Stachybotrys chartarum (ATCC 208877). This study employed a UVGI testing unit consisting of four chambers with a 9-W, Phillips, low pressure, mercury UVGI lamp in each chamber. The testing unit's apertures were adjusted to provide 50, 100, 150, and 200 µW/cm2 of uniform flux to the Petri dish surfaces, resulting in a total UVGI surface dose ranging from 12 to 144 mJ/cm2. The UVGI dose necessary to inactivate 90% of the S. chartarum was greater than the maximum dose of 144 mJ/cm2 evaluated in this study. While UVGI has been used to inactivate several strains of culturable fungal spores, S. chartarum was not susceptible to an appropriate dose of UVGI. The results of this study may not correlate directly to the effect of UVGI on airborne fungal spores. However, they indicate that current technology may not be efficacious as a supplement to ventilation unless it can provide higher doses of UVGI to kill spores, such as S. chartarum, traveling through the irradiated zone.Key words: Stachybotrys chartarum (synonyms S. atra, S. alternana), ultraviolet germicidal irradiation, fungi.

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Yang, Y., W. Y. Chan, C. L. Wu, R. Y. C. Kong, and A. C. K. Lai. "Minimizing the exposure of airborne pathogens by upper-room ultraviolet germicidal irradiation: an experimental and numerical study." Journal of The Royal Society Interface 9, no. 77 (July 18, 2012): 3184–95. http://dx.doi.org/10.1098/rsif.2012.0439.

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There has been increasing interest in the use of upper-room ultraviolet germicidal irradiation (UVGI) because of its proven effectiveness in disinfecting airborne pathogens. An improved drift flux mathematical model is developed for optimizing the design of indoor upper-room UVGI systems by predicting the distribution and inactivation of bioaerosols in a ventilation room equipped with a UVGI system. The model takes into account several bacteria removal mechanisms such as convection, turbulent diffusion, deposition and UV inactivation. Before applying the model, the natural die-off rate and susceptibility constants of bioaerosols were measured experimentally. Two bacteria aerosols, Escherichia coli and Serratia marcescens , were tested for this purpose. It was found out that the general decay trend of the bioaerosol concentration predicted by the numerical model agrees well with the experimental measurements. The modelling results agree better with experimental observations for the case when the UVGI inactivation mechanism dominates at the upper-room region than for the case without UVGI. The numerical results also illustrate that the spatial distribution of airborne bacteria was influenced by both air-flow pattern and irradiance distribution. In addition to predicting the local variation of concentration, the model assesses the overall performance of an upper-room UVGI system. This model has great potential for optimizing the design of indoor an upper-room UVGI systems.

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Menzies, Dick, Neill Adhikari, Marie Arietta, and Vivian Loo. "Efficacy of Environmental Measures in Reducing Potentially Infectious Bioaerosols During Sputum Induction." Infection Control & Hospital Epidemiology 24, no. 7 (July 2003): 483–89. http://dx.doi.org/10.1086/502242.

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AbstractObjective:To evaluate the airborne viable bacterial concentrations generated during sputum induction and their reduction with exhaust ventilation, ultraviolet germicidal irradiation (UVGI), or both.Methods:Exhaust ventilation, upper air UVGI lights, and a portable UVGI unit were operated independently or in combination while and after sputum induction was performed for 58 patients suspected of having active tuberculosis. Viable airborne bacteria were sampled with volumetric air samplers, grown on blood agar, and identified with standard techniques.Results:During and immediately after sputum induction, concentrations of airborne bacteria, particularly respiratory tract or oropharyngeal organisms, increased rapidly, regardless of environmental conditions. The subsequent rate of reduction of airborne bacteria was most rapid with the portable UVGI unit, followed by upper air UVGI with air mixing. Exhaust ventilation achieved high air changes per hour, but efficacy in reducing airborne bacterial concentrations was low. However, the continuous entrainment of bacteria-laden air from the hallway outside may have resulted in underestimation. The efficacy of a wall-mounted upper air UVGI fixture was significantly less if there was no air mixing. The irradiation from this fixture was of adequate germicidal intensity only in a narrow horizontal plane 2.5 m above the floor.Conclusion:Sputum induction was associated with a rapid and substantial increase in airborne bacteria despite the use of exhaust ventilation providing more than 30 air changes per hour, and the adjunct use of UVGI. This emphasizes that health-care workers involved in similar cough-inducing procedures performed for patients with suspected tuberculosis must wear appropriate personal respirators (Infect Control Hosp Epidemiol2003;24:483-489)

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Pegues, David A., Jennifer Han, Cheryl Gilmar, Brooke McDonnell, and Steven Gaynes. "Impact of Ultraviolet Germicidal Irradiation for No-Touch Terminal Room Disinfection on Clostridium difficile Infection Incidence Among Hematology-Oncology Patients." Infection Control & Hospital Epidemiology 38, no. 1 (October 6, 2016): 39–44. http://dx.doi.org/10.1017/ice.2016.222.

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OBJECTIVETo evaluate the impact of no-touch terminal room no-touch disinfection using ultraviolet wavelength C germicidal irradiation (UVGI) on C. difficile infection (CDI) rates on inpatient units with persistently high rates of CDI despite infection control measures.DESIGNInterrupted time-series analysis with a comparison arm.SETTING3 adult hematology-oncology units in a large, tertiary-care hospital.METHODSWe conducted a 12-month prospective valuation of UVGI. Rooms of patients with CDI or on contact precautions were targeted for UVGI upon discharge using an electronic patient flow system. Incidence rates of healthcare-onset CDI were compared for the baseline period (January 2013–December 2013) and intervention period (February 2014–January 2015) on study units and non–study units using a mixed-effects Poisson regression model with random effects for unit and time in months.RESULTSDuring a 52-week intervention period, UVGI was deployed for 542 of 2,569 of all patient discharges (21.1%) on the 3 study units. The CDI rate declined 25% on study units and increased 16% on non-study units during the intervention compared to the baseline period. We detected a significant association between UVGI and decrease in CDI incidence (incidence rate ratio [IRR], 0.49; 95% confidence interval [CI], 0.26–0.94; P=.03) on the study units but not on the non-study units. The impact of UVGI use on average room-cleaning time and turnaround time was negligible compared to the baseline period.CONCLUSIONSTargeted deployment of UVGI to rooms of high-risk patients at discharge resulted in a substantial reduction of CDI incidence without adversely impacting room turnaround.Infect Control Hosp Epidemiol 2016;1–6

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Lai, Ka M., Harriet A. Burge, and Melvin W. First. "Size and UV Germicidal Irradiation Susceptibility of Serratia marcescens when Aerosolized from Different Suspending Media." Applied and Environmental Microbiology 70, no. 4 (April 2004): 2021–27. http://dx.doi.org/10.1128/aem.70.4.2021-2027.2004.

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ABSTRACT Experimental systems have been built in laboratories worldwide to investigate the influence of various environmental parameters on the efficacy of UV germicidal irradiation (UVGI) for deactivating airborne microorganisms. It is generally recognized that data from different laboratories might vary significantly due to differences in systems and experimental conditions. In this study we looked at the effect of the composition of the suspending medium on the size and UVGI susceptibility of Serratia marcescens in an experimental system built in our laboratory. S. marcescens was suspended in (i) distilled water, (ii) phosphate buffer, (iii) 10% fetal calf serum, (iv) phosphate-buffered saline (saline, 0.8% sodium chloride), and (v) synthetic saliva (phosphate-buffered saline with 10% fetal calf serum). At low humidity (36%), S. marcescens suspended in water-only medium was the most susceptible to UVGI, followed by those in serum-only medium. The count median diameters (CMDs) for culturable particles from water-only and serum-only media were 0.88 and 0.95 μm, respectively, with the measurements based on their aerodynamic behavior. The bacteria suspended in phosphate buffer, synthetic saliva, and phosphate-buffered saline had similar UVGI susceptibility and CMD at 1.0, 1.4, and 1.5 μm, respectively. At high humidity (68%) the CMD of the particles increased by 6 to 16%, and at the same time UVGI susceptibility decreased, with the magnitude of decrease related to the type of suspending medium. In conclusion, the choice of suspending medium influenced both size and UVGI susceptibility of S. marcescens. These data are valuable for making comparisons and deciding on the use of an appropriate medium for various applications.

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Clark, Ewan M., Harry Wright, Kelly-Anne Lennon, Vicki A. Craik, Jason R. Clark, and John B. March. "Inactivation of Recombinant Bacteriophage Lambda by Use of Chemical Agents and UV Radiation." Applied and Environmental Microbiology 78, no. 8 (February 10, 2012): 3033–36. http://dx.doi.org/10.1128/aem.06800-11.

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ABSTRACTSeveral approaches for the inactivation of bacteriophage lambda, including UV germicidal irradiation (UVGI) and the chemical agents Virkon-S, Chloros, Decon-90, and sodium hydroxide (NaOH), were compared. Virkon, NaOH, and UVGI caused a ≥7-log10reduction in phage titers. This study successfully describes several methods with potential for bacteriophage inactivation in industrial settings.

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Sebastian Marcos, Patricia, Darren Hermes, and Mellora Sharman. "Comparative assessment of the effectiveness of three disinfection protocols for reducing bacterial contamination of stethoscopes." Infection Control & Hospital Epidemiology 41, no. 1 (November 7, 2019): 120–23. http://dx.doi.org/10.1017/ice.2019.308.

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AbstractIn a crossover study, 30 stethoscopes were assessed and disinfected using 3 protocols: isopropyl alcohol, a quaternary ammonia or biguanide disinfectant, and ultraviolet germicidal irradiation (UVGI). All protocols effectively reduced bacterial loads, but UVGI was less effective at higher contamination levels (P = .0004). The effectiveness of each intervention was short in duration.

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Chew, Chii Chii, and Philip Rajan. "Controversies on the Use of Ultraviolet Rays for Disinfection During the COVID-19 Pandemic." Malaysian Journal of Medical Sciences 28, no. 1 (February 24, 2021): 117–19. http://dx.doi.org/10.21315/mjms2021.28.1.15.

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During the coronavirus disease 2019 (COVID-19) pandemic, the use of ultraviolet (UV) rays to disinfect skin areas, clothes and other objects at the entry/exit points of public spaces has been widely discussed by stakeholders. While ultraviolet germicidal irradiation (UVGI) has been shown to effectively inactivate coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV)-1 and Middle East respiratory syndrome coronavirus (MERS-CoV), no specific evidence proves that it effectively inactivates the new SARS-CoV-2 virus that causes COVID-19. Because UV rays damage human tissue, UVGI should be used with caution and not directly on human skin. Various guidelines recommend that UVGI should not be used as a sole agent for disinfecting surfaces or objects but as an adjunct to the latest standard disinfecting procedures.

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Green, Christopher F., Laura A. Elbe, Tyler D. Neal, John J. Lowe, and Shawn G. Gibbs. "Ultraviolet germicidal irradiation susceptibility of methicillin-resistant Staphylococcus aureus compared with methicillin-susceptible S. aureus." Canadian Journal of Microbiology 61, no. 11 (November 2015): 871–75. http://dx.doi.org/10.1139/cjm-2015-0243.

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Antibiotic misuse and overuse in both the healthcare and agricultural fields have dramatically increased the prevalence of antibiotic resistance in human pathogens. Two strains of methicillin-resistant Staphylococcus aureus (MRSA) (ATCC 43330 and a wild-type) and 1 strain of methicillin-susceptible S. aureus (ATCC 25923) were challenged (9 runs in triplicate) in a preliminary study with ultraviolet germicidal irradiation (UVGI) doses ranging from 0.25 to 3.00 mJ/cm2. The mean percent kill was calculated for each strain when compared with the control plates (no exposure to UVGI). Then, each strain was challenged (22 runs in triplicate) with UVGI doses of 2.00, 2.50, and 3.00 mJ/cm2. The results suggest a difference between the doses required to disinfect surfaces with each strain. Assuming a standard error rate of α = 0.05, there was a significant difference in variance between the MRSA (ATCC 43330 and wild type) strains and the S. aureus (ATCC 25923) methicillin-susceptible strain.

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Salie, Faatiema, and Trust Saidi. "Potential of ultraviolet germicidal irradiation for infection prevention and control of SARS-CoV-2 in South Africa." Global Health Innovation 3, no. 2 (November 27, 2020): 1–10. http://dx.doi.org/10.15641/ghi.v3i2.1009.

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The response to the challenges arising during the COVID-19 pandemic has seen the rapid implementation of innovative technological solutions which have been built on established knowledge and resources. This has been reflected in infection, prevention and control practices (IPC) to minimise the transmission of the disease. In this article, we review ultraviolet germicidal irradiation (UVGI) as such a technology. We illustrate the way it has traditionally been used in airborne and surface disinfection strategies, and how it has, more recently, been adapted. UVGI has been widely used as an environmental IPC measure against tuberculosis in South Africa, though challenges have been experienced in the implementation of the technology in public healthcare facilities. This has resulted in the development of a knowledge and infrastructure base. We posit that, given the established UVGI resources in South Africa, the technology may be a viable environmental IPC solution for the COVID-19 period and beyond.

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Ludwig-Begall, Louisa F., Constance Wielick, Olivier Jolois, Lorène Dams, Ravo M. Razafimahefa, Hans Nauwynck, Pierre-Francois Demeuldre, et al. "“Don, doff, discard” to “don, doff, decontaminate”—FFR and mask integrity and inactivation of a SARS-CoV-2 surrogate and a norovirus following multiple vaporised hydrogen peroxide-, ultraviolet germicidal irradiation-, and dry heat decontaminations." PLOS ONE 16, no. 5 (May 19, 2021): e0251872. http://dx.doi.org/10.1371/journal.pone.0251872.

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Background As the SARS-CoV-2 pandemic accelerates, the supply of personal protective equipment remains under strain. To combat shortages, re-use of surgical masks and filtering facepiece respirators has been recommended. Prior decontamination is paramount to the re-use of these typically single-use only items and, without compromising their integrity, must guarantee inactivation of SARS-CoV-2 and other contaminating pathogens. Aim We provide information on the effect of time-dependent passive decontamination (infectivity loss over time during room temperature storage in a breathable bag) and evaluate inactivation of a SARS-CoV-2 surrogate and a non-enveloped model virus as well as mask and respirator integrity following active multiple-cycle vaporised hydrogen peroxide (VHP), ultraviolet germicidal irradiation (UVGI), and dry heat (DH) decontamination. Methods Masks and respirators, inoculated with infectious porcine respiratory coronavirus or murine norovirus, were submitted to passive decontamination or single or multiple active decontamination cycles; viruses were recovered from sample materials and viral titres were measured via TCID50 assay. In parallel, filtration efficiency tests and breathability tests were performed according to EN standard 14683 and NIOSH regulations. Results and discussion Infectious porcine respiratory coronavirus and murine norovirus remained detectable on masks and respirators up to five and seven days of passive decontamination. Single and multiple cycles of VHP-, UVGI-, and DH were shown to not adversely affect bacterial filtration efficiency of masks. Single- and multiple UVGI did not adversely affect respirator filtration efficiency, while VHP and DH induced a decrease in filtration efficiency after one or three decontamination cycles. Multiple cycles of VHP-, UVGI-, and DH slightly decreased airflow resistance of masks but did not adversely affect respirator breathability. VHP and UVGI efficiently inactivated both viruses after five, DH after three, decontamination cycles, permitting demonstration of a loss of infectivity by more than three orders of magnitude. This multi-disciplinal approach provides important information on how often a given PPE item may be safely reused.

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Lungu, Catalin, and Ilinca Nastase. "Brief overview on the UVGI disinfection technology." Revista Romana de Inginerie Civila/Romanian Journal of Civil Engineering 12, no. 2 (June 25, 2021): 207–27. http://dx.doi.org/10.37789/rjce.2021.12.2.1.

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Kowalski, W. J., W. P. Bahnfleth, and J. L. Rosenberger. "Dimensional Analysis of UVGI Air Disinfection Systems." HVAC&R Research 9, no. 3 (July 1, 2003): 347–63. http://dx.doi.org/10.1080/10789669.2003.10391074.

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Maal-Bared, Rasha, and Jennifer Loudon. "Strategies for managing N95 mask shortages at water resource recovery facilities during pandemics: a review." Water Science and Technology 82, no. 12 (November 9, 2020): 2798–812. http://dx.doi.org/10.2166/wst.2020.537.

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Abstract As the numbers of COVID-19 cases grew globally, the severe shortages of health care respiratory protective equipment impacted the ability of water resource recovery facilities (WRRFs) to acquire N95 masks for worker protection. While the Occupational Safety and Health Administration (OSHA) encourages WRRFs to conduct job safety assessments to mitigate risks from bioaerosols, it does not provide clear guidance on respiratory protection requirements, leaving the use of N95 masks across the industry non-standardized and difficult to justify. Strategies need to be developed to cope with shortages during pandemics, and these should take into consideration a WRRF's size and disinfection equipment available. Our objective is to provide an overview of respiratory protection-related practices recommended for health care professionals that apply to WRRFs (e.g., elimination, substitution, extended use, reuse, disinfection). Reviewed N95 mask disinfection strategies included using hydrogen peroxide, autoclaving, moist heat, dry heat, ultraviolet germicidal irradiation (UVGI), ethylene oxide, chlorine and ethanol. Of these, dry heat, autoclaving and UVGI present the most promise for WRRFs, with UVGI being limited to larger utilities. We recommend that WRRFs work closely with disinfection technology manufacturers, mask providers, health and safety staff and inspectors to develop suitable programs to cope with N95 mask shortages during pandemics.

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Restuti, Ratna Dwi, Harim Priyono, Rangga Rayendra Saleh, Ayu Astria Sriyana, Prasandhya Astagiri Yusuf, Tri Juda Airlangga, Ari Prayitno, Gortap Sitohang, Fitri Arman, and Suko Dwi Priyanto. "The Effectiveness of Cipto Mangunkusumo Hospital Ultraviolet Germicidal Irradiation (UVGI) Chamber for N95 Respirators Disinfection in COVID-19 pandemics: A Preliminary Study." Journal Of The Indonesian Medical Association 72, no. 1 (June 19, 2022): 16–22. http://dx.doi.org/10.47830/jinma-vol.72.1-2022-583.

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Introduction: During the COVID-19 pandemic, where the disease might spread in a medical facility setting, the common problems found in every country is the shortage of personal protective equipment (PPE) for medical personnel – especially the disposable N95 respirators. Thus, a higher amplitude to disinfect and reuse N95 is urgently needed. In this study, we designed an effective and safe disinfection methods through an Ultraviolet Germicidal Irradiation (UVGI) chamber in Dr. Cipto Mangunkusumo Hospital to control the shortage of PPE by disinfecting and reusing disposable N95 respirators. Purpose: To evaluate the dosage and effectiveness of UV-C radiation for disposable N95 respirators disinfection in our designated UVGI chamber. Methods: This study used a cross-sectional design to determine the dose and the effectiveness of UV-C radiation in eradicating SARS-CoV 2 on disposable N95 respirators. Results: Using two different distances from the light source, we confirmed the inverse square law of UV-C radiation power. Irradiation for 2 hours with a radiation dose of 1080 mJ/cm2 resulted in undetected SARS-CoV-2 gene based on PCR examination in 10 out of 10 samples. Conclusion: This UVGI chamber is a potential solution for hospitals or medical facilities to overcome the limitations that occurred in the pandemic by disinfecting PPE.

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Bang, Jong-Il, Jeongyeon Park, Anseop Choi, Jae-Weon Jeong, Jin Kim, and Minki Sung. "Evaluation of UR-UVGI System for Sterilization Effect on Microorganism Contamination in Negative Pressure Isolation Ward." Sustainability 10, no. 9 (September 6, 2018): 3192. http://dx.doi.org/10.3390/su10093192.

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A negative pressure isolation ward prevents the outflow of airborne microorganisms from inside the ward, minimizing the spread of airborne contamination causing respiratory infection. In response to recent outbreaks of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), Korea has increased the number of these facilities. However, airborne contaminants that flow into the ward from adjacent areas may cause secondary harm to patients. In this study, the sterilization effect of upper-room ultraviolet germicidal irradiation (UR-UVGI) on microorganisms generated within the negative pressure isolation ward and those flowing inward from adjacent areas was evaluated through field experiments and computational fluid dynamics (CFD) analysis, to assess the potential of this approach as a supplementary measure to control such microorganisms. The sterilization effect was found to be not high because of high-level ventilation. CFD analysis under various conditions shows that the sterilization effect for indoor-generated microorganisms varies with the level of UV radiation, the source locations of the indoor-generated microorganisms, air supplies and exhausts, the UVGI system, and the airflow formed under the specified conditions. Our results show that when the UVGI system is installed in the upper part of the ward entrance, contaminated air from adjacent area is strongly sterilized.

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Gopalan, Thirumaaran, Rabi’atul ‘Adawiyah Mohd Yatim, Mohd Ridha Muhamad, Nor Shafina Mohamed Nazari, N. Awanis Hashim, Jacob John, and Victor Chee Wai Hoe. "Decontamination Methods of N95 Respirators Contaminated with SARS-CoV-2." Sustainability 13, no. 22 (November 11, 2021): 12474. http://dx.doi.org/10.3390/su132212474.

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In the preparation and response to the COVID-19 pandemic, a sufficient supply of personal protective equipment (PPE), particularly the face mask, is essential. Shortage of PPE due to growing demand leaves health workers at significant risk as they fight this pandemic on the frontline. As a mitigation measure to overcome potential mask shortages, these masks could be decontaminated and prepared for reuse. This review explored past scientific research on various methods of decontamination of the N95-type respirators and their efficiency against the SARS-CoV-2 virus. Ultraviolet germicidal irradiation (UVGI) and hydrogen peroxide vapor (HPV) show great potential as an effective decontamination system. In addition, UVGI and HPV exhibit excellent effectiveness against the SARS-CoV-2 virus on the N95 respirator surfaces.

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Lee, In-Ho, Jong-Il Bang, An-Na Won, and Jung-Ha Hwang. "Comparison of IAQ with Air Filter and UVGI in HVAC System." Journal of The Korean Society of Living Environmental System 25, no. 6 (December 31, 2018): 712–21. http://dx.doi.org/10.21086/ksles.2018.12.25.6.712.

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Kouropoulos, Giorgos. "THE EFFECT OF REYNOLDS NUMBER OF AIR FLOW DURING THE AIR STERILIZATION PROCESS WITH ULTRAVIOLET GERMICIDAL IRRADIATION LAMP." ASEAN Engineering Journal 11, no. 3 (April 21, 2021): 1–12. http://dx.doi.org/10.11113/aej.v11.16868.

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This case study examines the effect that the Reynolds number of air flow has on the population oflive pathogenic microorganisms during the process of air sterilization using ultraviolet germicidalirradiation (UVGI) lamp in a closed air-duct. With this aim, the first discussion is the mathematicalmodel which regulates changes to the Reynolds number in terms of the percentage of populationfor the following live pathogenic microorganisms: Escherichia coli, Mycobacterium tuberculosisand Streptococcus pneumoniae, under special condition of flow rate and intensity of UVirradiation. In conclusion, as the velocity and the Reynolds number of the air flow in the ductincreases, the exposure time of the pathogens to the field of UV-C irradiation decreases, theeffect of UV-C irradiation and the germicide capabilities of the UVGI lamp are reduced.Consequently, the population of live pathogenic microorganisms increases.

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Liu, Tseng, Wang, Dai, and Shih. "The Study of an Ultraviolet Radiation Technique for Removal of the Indoor Air Volatile Organic Compounds and Bioaerosol." International Journal of Environmental Research and Public Health 16, no. 14 (July 17, 2019): 2557. http://dx.doi.org/10.3390/ijerph16142557.

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This study examined the use of high dosages of ultraviolet germicidal irradiation (UVGI) (253.7 nm) to deal with various concentrations of air pollutants, such as formaldehyde (HCHO), total volatile organic compounds (TVOC), under various conditions of humidity. A number of irradiation methods were applied for various durations in field studies to examine the efficiency of removing HCHO, TVOC, bacteria, and fungi. The removal efficiency of air pollutants (HCHO and bacteria) through long-term exposure to UVGI appears to increase with time. The effects on TVOC and fungi concentration were insignificant in the first week; however, improvements were observed in the second week. No differences were observed regarding the removal of HCHO and TVOC among the various irradiation methods in this study; however significant differences were observed in the removal of bacteria and fungi.

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SUNG, Minki, Shinsuke KATO, and Tsutsumi TANAKA. "METHOD TO EVALUATE GERMICIDAL EFFICIENCY OF UR-UVGI SYSTEM." Journal of Environmental Engineering (Transactions of AIJ) 74, no. 639 (2009): 621–27. http://dx.doi.org/10.3130/aije.74.621.

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S, Sathyavathi, Nandini M P, Prasanna Simha Mohan Rao, Prabhu Manohar, Naveena J, and Kavitha K. "Validation of N95 respirator mask for the Re-use in the pandemic crisis." IP International Journal of Medical Microbiology and Tropical Diseases 7, no. 4 (November 15, 2021): 232–36. http://dx.doi.org/10.18231/j.ijmmtd.2021.048.

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The SARS COVID 19 (Severe Acute Respiratory Syndrome Corona Virus Disease 2019) pandemic has created a surge in the need for N95 respirators all across the world. Health care systems are struggling to find a way to cleanse and decontaminate the N95 masks for reuse. To combat the crisis there is a need to validate the N95 mask for efficiency and air filterability on repeated exposure to UV irradiation and vaporized hydrogen peroxide with equal parts of normal saline. To validate N95 respirator mask by using UVGI (Ultra Violet Germicidal Irradiation) method using UV hood and VHP (Vaporized Hydrogen peroxide 6% with equal volume saline 0.9% using an OT fogger machine). VHP decontamination is the method of choice to repeatedly re-sterilize N95 masks. Decontamination by the VHP method is more efficient in killing microorganisms within a short duration of exposure (60 minutes). The method retains the texture of the mask material, re-usability and air filterability even with repeated exposure (up to 10 times). UVGI does sterilize the mask but is inferior to VHP in retaining air filterability.

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Gilkeson, Carl A., and Catherine Noakes. "Application of CFD Simulation to Predicting Upper-Room UVGI Effectiveness." Photochemistry and Photobiology 89, no. 4 (November 28, 2012): 799–810. http://dx.doi.org/10.1111/php.12013.

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Motta-Ávila, Carlos Alberto, María Guadalupe Flores -Sánchez, Diego Gutiérrez-González, Arturo Rodríguez-Cristerna, and Joaquín Miranda-Germán. "Robot terrestre autónomo auxiliar en la desinfección o sanitización de interiores mediante luz UV-C." Memorias del Concurso Lasallista de Investigación, Desarrollo e innovación 8, no. 1 (January 13, 2022): 38–39. http://dx.doi.org/10.26457/mclidi.v8i1.3153.

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Muchas enfermedades se transmiten o contagian de persona a persona a través de virus que viajan en gotitas expulsadas por la boca y nariz, sobre todo cuando el huésped de la enfermedad tose, estornuda, o habla. Esto ha tomado mayor relevancia cuando ocurren enfermedades pandémicas como el coronavirus (SARS-CoV-2 o COVID-19) o la influenza H1N1. Para el caso del COVID-19 se determinó que los virus pueden sobrevivir en algunas superficies según el material de estas, así, es posible que alguien pudiera quedar contagiado después de entrar en contacto con estas superficies y llevar los virus a sus vías respiratorias. Se ha demostrado que la luz ultravioleta desactiva a algunos tipos de virus. Esta técnica de sanitización por medio de luz ultravioleta se denomina en inglés “Ultraviolet germicidal irradiation” (UVGI). El objetivo de este trabajo fue diseñar y construir un dispositivo robótico equipado con luz UV-C, capaz de navegar de forma autónoma en una habitación, de forma que se maximice la radiación y por consecuencia garantizar la limpieza de las superficies. Ya que el robot debe resguardar ante todo la seguridad de las personas, contará con un sistema de detección de movimiento o de presencia, el cual desactivará inmediatamente las luces y realizar una bitácora o plataforma informática de seguimiento, en la cual se pueda consultar en que habitaciones ha trabajado el robot que permite administrar sanitizaciones periódicas, así como agendarlas acorde al número de personas que hayan estado presentes en una habitación, oficina o auditorio. El proyecto constó de varias etapas: En la primera etapa se consideró el diseño del sistema UVGI de forma independiente al desarrollo del robot autónomo al que se le va a equipar. Esto permite tener un sistema “básico” de UV-C, para comenzar su uso por un operador; y la plataforma web de seguimiento permitirá capturar una bitácora de uso del sistema básico. A la par se hizo el diseño del robot, para navegar de forma autónoma en interiores, el sistema de detección de presencia humana, y el sistema UVGI integrado. En la segunda etapa, se consideró la integración del sistema UVGI al robot autónomo. Se realizaron pruebas y mejoras de los sistemas del robot para mapeo, navegación, presencia, y activación del sistema UVGI. Así como la actualización automática desde el robot al sistema web de administración. Para ambas etapas y pruebas, durante el desarrollo del proyecto, se consideran las instalaciones de la Universidad La Salle México, principalmente salones de clase, oficinas, salas de juntas, e incluso auditorios. La validación se realiza colocando instrumentos de control dentro de la sala o habitación, y evaluarlos con microscopia o prueba de esterilización. La universidad es un espacio ideal para el uso de esta tecnología, ya que es un entorno estructurado, los espacios son compartidos a lo largo del día, y puede realizarse de manera periódica la desinfección, coadyuvando con el personal de limpieza. Algunas de las ventajas para las pruebas iniciales de este sistema son: la universidad tiene un excelente sistema de gestión de espacios, pudiendo localizar que salones, salas de juntas, entre otras, existen y cuando se van a utilizar; el personal de limpieza tiene bien definidos roles horarios y de espacios. La plataforma o bitácora tendría toda esta información capturada para realizar o proponer sesiones de desinfección. Dentro de los impactos y resultados esperados se tiene un sistema robotizado UVGI autónomo para la desinfección satisfactoria en los espacios donde se active el sistema, siendo las pruebas y uso inicial en la Universidad La Salle México. Se diseñó una plataforma inteligente, que permita además de dar seguimiento al robot, estimar lugares frecuentados por días y horas, y alertar para realizar desinfección. Como perspectiva se considera hacer el sistema robusto para operar de forma autónoma durante horas no laborables, por ejemplo, durante la noche y madrugada, para garantizar que los espacios estén desinfectados al retorno de actividades y ofrecer el servicio de desinfección una vez que el sistema integral se valide y se encuentre operando satisfactoriamente, y para uso en otros espacios como son: instituciones educativas, salas de cine, edificios de oficinas, casas de reposo, edificios o complejos multifamiliares, e incluso hospitales.

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Schnell, Eric, Elham Karamooz, Melanie J. Harriff, Jane E. Yates, Christopher D. Pfeiffer, and Stephen M. Smith. "Construction and validation of an ultraviolet germicidal irradiation system using locally available components." PLOS ONE 16, no. 7 (July 23, 2021): e0255123. http://dx.doi.org/10.1371/journal.pone.0255123.

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Coronavirus disease (COVID-19), the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, is responsible for a global pandemic characterized by high transmissibility and morbidity. Healthcare workers (HCWs) are at risk of contracting COVID-19, but this risk has been mitigated through the use of personal protective equipment such as N95 Filtering Facepiece Respirators (FFRs). At times the high demand for FFRs has exceeded supply, placing HCWs at increased exposure risk. Effective FFR decontamination of many FFR models using ultraviolet-C germicidal irradiation (UVGI) has been well-described, and could maintain respiratory protection for HCWs in the face of supply line shortages. Here, we detail the construction of an ultraviolet-C germicidal irradiation (UVGI) device using previously existing components available at our institution. We provide data on UV-C dosage delivered with our version of this device, provide information on how users can validate the UV-C dose delivered in similarly constructed systems, and describe a simple, novel methodology to test its germicidal effectiveness using in-house reagents and equipment. As similar components are readily available in many hospitals and industrial facilities, we provide recommendations on the local construction of these systems, as well as guidance and strategies towards successful institutional implementation of FFR decontamination.

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Harmawan Febrianto, Massus Subekti, and Nur Hanifah Yuninda. "PENGEMBANGAN ALAT DESINFEKSI AIR MINUM DENGAN UVGI (ULTRAVIOLET GERMECIDAL IRRADIATION) BERBASIS ARDUINO." Journal of Electrical Vocational Education and Technology 2, no. 1 (March 21, 2020): 1–5. http://dx.doi.org/10.21009/jevet.0021.01.

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The purpose of this study is to make a drinking water desinfector device by irradiating ultraviolet light (UV) based on Arduino. The device can provide information specific to large-intensity UV lamps in optimal perfomance to desinfection drinking water, as well as a signal to the operator if, the intensity of the UV lamps has decreased resulting in water flow will be closed automatically controlled by on Arduino. This study uses a method of Research and Development (Research and Development), which includes planning, requirements analysis, design, and implementation of the system. System requirements necessary in this study are ultraviolet sensor that can measure the magnitude and intensity of ultraviolet rays water rate sensor to measure the flow rate of water entering on this instrument. In this case serves to monitor the UV lamp specifically keoptimalan and Arduino will process the input results for the solenoid valve opens automatically and gives an alarm signal to the operator. These results indicate that the instrument disinfection of drinking water with UVGI-based Arduino has managed to work out where these tools can provide large information intensity of UV rays as well, can give an alarm signal to the operator and the control solenoid valve in order to shut off the flow of water automatically as a follow security if not in accordance with a predetermined set point, namely at the point of maximum 978 lux with a water flow rate 3 L / min based microbial testing in the laboratory. At this point is the most optimal point in reducing bacteria which amounted to 94.57% or the remaining 25 colonies / ml of the total number of bacteria before exposed to UV light that is 460 colonies / ml. It is adjusted by the standard (SNI 7388: 2009-14.1.1.2) with a maximum limit of microbial contamination in drinking water is 100 colonies / ml. Abstrak Tujuan penelitian ini adalah membuat suatu alat desinfeksi air minum dengan penyinaran lampu ultraviolet (UV) berbasis Arduino. Alat ini dapat memberikan informasi secara spesifik terhadap besar intesitas lampu UV dalam keoptimalannya untuk medesinfeksikan air minum, serta memberikan sinyal kepada operator apabila, intesitas lampu UV telah menurun dan akan mengakibatkan aliran air akan tertutup secara otomatis yang dikendalikan dengan Arduino. Penelitian ini menggunakan Metode Penelitian dan Pengembangan (Research and Development) yang meliputi perencanaan, analisis kebutuhan, perancangan, dan implementasi sistem. Kebutuhan sistem yang diperlukan pada penelitian ini adalah : sensor ultraviolet yang dapat mengukur besar intesitas sinar ultraviolet dan sensor laju air untuk mengukur kecepatan aliran air yang masuk pada alat ini. Dalam hal ini berfungsi memantau keoptimalan lampu UV secara spesifik serta Arduino akan memproses hasil input tersebut untuk membuka solenoid valve secara otomatis dan memberikan sinyal alarm kepada operator. Hasil penelitian ini menunjukan bahwa alat desinfeksi air minum dengan UVGI berbasis Arduino telah berhasil bekerja dimana alat ini dapat memberikan informasi besar intesitas sinar UV serta, dapat memberikan sinyal alarm kepada operator dan mengendalikan solenoid valve agar bisa menutup aliran air secara otomatis sebagai tindak keamanan jika tidak sesuai dengan set point yang telah ditentukan, yakni pada titik maksimal 978 lux dengan kecepatan aliran air 3 L/min berdasarkan pengujian mikroba di laboratorium. Pada titik ini adalah titik yang paling optimal dalam mereduksi bakteri yakni sebesar 94,57% atau tersisa 25 Koloni/ml dari angka total bakteri sebelum disinari sinar UV yakni 460 koloni/ml . Hal ini disesuaikan oleh standar (SNI 7388:2009-14.1.1.2) dengan batas maksimum cemaran mikroba pada air minum sebesar 100 koloni/ml.

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Wan Yunoh, Wan Syazlin, Roha Tukimin, Naurah Mat Isa, Mohd Yusof Hamzah, and Khairul Azhar Abdul Halim. "A study on UVC irradiance emitted by various types of UVGI products." IOP Conference Series: Materials Science and Engineering 1106, no. 1 (March 1, 2021): 012008. http://dx.doi.org/10.1088/1757-899x/1106/1/012008.

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Zhang, John, Robert Levin, Robert Angelo, Richard Vincent, Philip Brickner, Peter Ngai, and Edward A. Nardell. "A Radiometry Protocol for UVGI Fixtures Using a Moving-Mirror Type Gonioradiometer." Journal of Occupational and Environmental Hygiene 9, no. 3 (March 2012): 140–48. http://dx.doi.org/10.1080/15459624.2011.648569.

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Green, Christopher F., and Pasquale V. Scarpino. "The use of ultraviolet germicidal irradiation (UVGI) in disinfection of airborne bacteria." Environmental Engineering and Policy 3, no. 1 (March 2001): 101–7. http://dx.doi.org/10.1007/s100220100046.

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Choi, Sang-Gon. "A Study on simulation analysis of UVGI air sterilizer installation in a car for microbiological safety." Journal of the Korea Safety Management and Science 16, no. 3 (September 30, 2014): 279–87. http://dx.doi.org/10.12812/ksms.2014.16.3.279.

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Thornton, Gail M., Brian A. Fleck, Natalie Fleck, Emily Kroeker, Dhyey Dandnayak, Lexuan Zhong, and Lisa Hartling. "The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: A systematic review of ultraviolet radiation." PLOS ONE 17, no. 4 (April 8, 2022): e0266487. http://dx.doi.org/10.1371/journal.pone.0266487.

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Respiratory viruses are capable of transmitting via an aerosol route. Emerging evidence suggests that SARS-CoV-2 which causes COVID-19 can be spread through airborne transmission, particularly in indoor environments with poor ventilation. Heating, ventilation, and air conditioning (HVAC) systems can play a role in mitigating airborne virus transmission. Ultraviolet germicidal irradiation (UVGI), a feature that can be incorporated into HVAC systems, can be used to impede the ability of viruses to replicate and infect a host. We conducted a systematic review of the scientific literature examining the effectiveness of HVAC design features in reducing virus transmission—here we report results for ultraviolet (UV) radiation. We followed international standards for conducting systematic reviews and developed an a priori protocol. We conducted a comprehensive search to January 2021 of published and grey literature using Ovid MEDLINE, Compendex, and Web of Science Core. Two reviewers were involved in study selection, data extraction, and risk of bias assessments. We presented study characteristics and results in evidence tables, and synthesized results across studies narratively. We identified 32 relevant studies published between 1936 and 2020. Research demonstrates that: viruses and bacteriophages are inactivated by UV radiation; increasing UV dose is associated with decreasing survival fraction of viruses and bacteriophages; increasing relative humidity is associated with decreasing susceptibility to UV radiation; UV dose and corresponding survival fraction are affected by airflow pattern, air changes per hour, and UV device location; and UV radiation is associated with decreased transmission in both animal and human studies. While UV radiation has been shown to be effective in inactivating viruses and reducing disease transmission, practical implementation of UVGI in HVAC systems needs to consider airflow patterns, air changes per hour, and UV device location. The majority of the scientific literature is comprised of experimental, laboratory-based studies. Further, a variety of viruses have been examined; however, there are few studies of coronaviruses and none to date of SARS-CoV-2. Future field studies of UVGI systems could address an existing research gap and provide important information on system performance in real-world situations, particularly in the context of the current COVID-19 pandemic. This comprehensive synthesis of the scientific evidence examining the impact of UV radiation on virus transmission can be used to guide implementation of systems to mitigate airborne spread and identify priorities for future research. Trial registration PROSPERO 2020 CRD42020193968.

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Khan, M. A., A. Ikram, S. Savul, F. K. Lalani, M. A. Khan, and M. Sarfraz. "Decontamination and Reuse of N95 Masks: A Narrative Review." Canadian Journal of Infectious Diseases and Medical Microbiology 2020 (November 25, 2020): 1–9. http://dx.doi.org/10.1155/2020/8869472.

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Background. The COVID-19 pandemic has presented an unprecedented strain on healthcare supplies. Currently there is a global shortage of personal protective equipment (PPE), especially N95 masks. In order to safeguard healthcare personnel in this critical time and to mitigate shortages of N95 respirators, reuse of N95 respirators has to be considered. Methods. Using PubMed and Science Direct, a literature search was conducted to find and synthesize relevant literature on decontamination of N95 respirators for their subsequent reuse. Peer-reviewed publications related to methods of decontamination from January 2007 to April 2020 in the English language are included in this narrative review. Bibliographies of articles for relevant literature were also scrutinized. Findings. A total of 19 studies are included in this narrative review. The appraised methods include ultraviolet germicidal irradiation (UVGI), moist heat incubation (MHI), ethylene oxide (EtO), hydrogen peroxide vapor (HPV), microwave steam bags (MSB), microwave-generated steam (MGS), dry microwave oven irradiation, hydrogen peroxide gas plasma (HPGP), dry heat, liquid hydrogen peroxide, and bleach and alcohol. Conclusion. In light of the COVID-19 pandemic, reuse of N95 respirators, although suboptimal, can be considered. Evidence reveals that UVGI, MHI, and HPV are amongst the safest and efficacious methods for decontamination of N95 masks. More research is needed to establish the safety and effectiveness of MGS, MSB, dry heat, EtO, liquid hydrogen peroxide, and HPGP. Alcohol, microwave irradiation, and bleach are not recommended because they damage N95 respirators.

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Bang, Jong-Il, An-Na Won, Jung-Ha Hwang, and Minki Sung. "An Analysis of the Sterilization Effect on UR-UVGI System for Out Patient Department at a General Hospital." Journal of The Korean Society of Living Environmental System 25, no. 6 (December 31, 2018): 769–76. http://dx.doi.org/10.21086/ksles.2018.12.25.6.769.

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Nardell, Edward, Richard Vincent, and David H. Sliney. "Upper-Room Ultraviolet Germicidal Irradiation (UVGI) for Air Disinfection: A Symposium in Print." Photochemistry and Photobiology 89, no. 4 (July 2013): 764–69. http://dx.doi.org/10.1111/php.12098.

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Nunayon, Sunday S., Huihui Zhang, and Alvin C. K. Lai. "Comparison of disinfection performance of UVC‐LED and conventional upper‐room UVGI systems." Indoor Air 30, no. 1 (December 2019): 180–91. http://dx.doi.org/10.1111/ina.12619.

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Lau, Josephine, William Bahnfleth, and James Freihaut. "Estimating the effects of ambient conditions on the performance of UVGI air cleaners." Building and Environment 44, no. 7 (July 2009): 1362–70. http://dx.doi.org/10.1016/j.buildenv.2008.05.015.

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Kanaan, Mohamad, Nesreene Ghaddar, and Kamel Ghali. "Localized air-conditioning with upper-room UVGI to reduce airborne bacteria cross-infection." Building Simulation 9, no. 1 (August 31, 2015): 63–74. http://dx.doi.org/10.1007/s12273-015-0250-7.

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Jacobs, Neva, Kathy Chan, Veruscka Leso, Andrea D’Anna, Dana Hollins, and Ivo Iavicoli. "A critical review of methods for decontaminating filtering facepiece respirators." Toxicology and Industrial Health 36, no. 9 (September 2020): 654–80. http://dx.doi.org/10.1177/0748233720964652.

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Various decontamination methods that may be used to extend respirator inventories have been examined for over a decade. In light of the ongoing coronavirus disease 2019 pandemic, many health-care settings are now implementing these techniques amid respirator shortages. We sought to perform a critical review of the available literature regarding decontamination methods to determine which strategies are effective at inactivating the target organism, preserve performance (filter efficiency and fit) of the respirator, leave no residual toxicity from the treatment, and are fast-acting, inexpensive, and readily available. We also identified areas for future research. We found that ultraviolet germicidal irradiation (UVGI) is the most widely studied method, and treatments are effective at inactivating SARS-CoV-2 without diminishing filtration efficiency or fit. These treatments were found to leave no residual toxicity for the wearer, have a relatively short cycle time of less than 1 h, and existing systems can likely be retrofitted to accommodate this method. Further, UVGI (among other treatment methods) has been recommended by the Centers for Disease Control and Prevention (CDC), Occupational Safety and Health Administration (OSHA), and respirator manufacturers. Methods involving microwave-generated steam also show potential in that they are likely effective against SARS-CoV-2, preserve performance, have no residual toxicity, require a short duration treatment cycle (often less than 10 min), and microwave ovens are inexpensive and readily available. Steam methods are currently recommended by the CDC, OSHA, and manufacturers. These respirator decontamination methods are likely also useful against other viruses or pathogens.

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Vernez, David, Jonathan Save, Anne Oppliger, Nicolas Concha-Lozano, Nancy B. Hopf, Hélène Niculita-Hirzel, Grégory Resch, et al. "Reusability of filtering facepiece respirators after decontamination through drying and germicidal UV irradiation." BMJ Global Health 5, no. 10 (October 2020): e003110. http://dx.doi.org/10.1136/bmjgh-2020-003110.

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IntroductionDuring pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an essential role in protecting healthcare personnel. The recycling of respirators is possible in case of critical shortage, but it raises the question of the effectiveness of decontamination as well as the performance of the reused respirators.MethodDisposable respirators were subjected to ultraviolet germicidal irradiation (UVGI) treatment at single or successive doses of 60 mJ/cm2 after a short drying cycle (30 min, 70°C). The germicidal efficacy of this treatment was tested by spiking respirators with two staphylococcal bacteriophages (vB_HSa_2002 and P66 phages). The respirator performance was investigated by the following parameters: particle penetration (NaCl aerosol, 10–300 nm), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry and mechanical tensile tests.ResultsNo viable phage particles were recovered from any of the respirators after decontamination (log reduction in virus titre >3), and no reduction in chemical or physical properties (SEM, particle penetrations <5%–6%) were observed. Increasing the UVGI dose 10-fold led to chemical alterations of the respirator filtration media (FTIR) but did not affect the physical properties (particle penetration), which was unaltered even at 3000 mJ/cm2 (50 cycles). When respirators had been used by healthcare workers and undergone decontamination, they had particle penetration significantly greater than never donned respirators.ConclusionThis decontamination procedure is an attractive method for respirators in case of shortages during a SARS pandemic. A successful implementation requires a careful design and particle penetration performance control tests over the successive reuse cycles.

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Schafer, Millie P., Elmira Kujundzic, Clyde E. Moss, and Shelly L. Miller. "Method for Estimating Ultraviolet Germicidal Fluence Rates in a Hospital Room." Infection Control & Hospital Epidemiology 29, no. 11 (November 2008): 1042–47. http://dx.doi.org/10.1086/591856.

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Background.Upper-room air UV germicidal irradiation (UVGI) is an effective environmental control measure for mitigating the transmission of airborne infections. Many factors influence the efficacy of an upper-room air UVGI system, including the levels and distribution of radiation. The radiation levels experienced by airborne microorganisms can be estimated by measuring the fluence rate, which is the irradiance from all angles that is incident on a small region of space.Methods.The fluence rate can be estimated by use of a radiometer coupled to a planar detector. Measurements in 4 directions at a single point are taken and summed to estimate the fluence rate at that point. This measurement process is repeated at different sites in the room at a single height.Results.In the upper air of a test room, the UV fluence rate varied at least 3-fold, with the maximum rate occurring in the immediate vicinity of the fixtures containing lamps emitting UV radiation. In the area that would be occupied by the patient and/or healthcare personnel, no significant variation occurred in the UV fluence rate for a designated height. There was no significant statistical difference between measurements obtained by different individuals, by using a different alignment, or during 5 observation periods. Lamp failures were detected on multiple occasions.Conclusion.This method is simple, requires no specialized training, and permits regular monitoring of the necessary UV fluence rates needed to sustain the targeted airborne microorganisms' inactivation level. Additionally, this method allowed for the detection of changes in UV fluence rates in the upper air of the simulated hospital room.

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Paul, Diptanu, Ayush Gupta, and Anand Kumar Maurya. "Exploring options for reprocessing of N95 Filtering Facepiece Respirators (N95-FFRs) amidst COVID-19 pandemic: A systematic review." PLOS ONE 15, no. 11 (November 20, 2020): e0242474. http://dx.doi.org/10.1371/journal.pone.0242474.

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Background There is global shortage of Personal Protective Equipment due to COVID-19 pandemic. N95 Filtering Facepiece Respirators (N95-FFRs) provide respiratory protection against respiratory pathogens including SARS-CoV-2. There is scant literature on reprocessing methods which can enable reuse of N95-FFRs. Aim We conducted this study to evaluate research done, prior to COVID-19 pandemic, on various decontamination methods for reprocessing of N95-FFRs. Methods We searched 5 electronic databases (Pubmed, Google Scholar, Crossref, Ovid, ScienceDirect) and 1 Grey literature database (OpenGrey). We included original studies, published prior to year 2020, which had evaluated any decontamination method on FFRs. Studies had evaluated a reprocessing method against parameters namely physical changes, user acceptability, respirator fit, filter efficiency, microbicidal efficacy and presence of chemical residues post-reprocessing. Findings and conclusions Overall, we found 7887 records amongst which 17 original research articles were finally included for qualitative analysis. Overall, 21 different types of decontamination or reprocessing methods for N95-FFRs were evaluated. Most commonly evaluated method for reprocessing of FFRs was Ultraviolet (Type-C) irradiation (UVGI) which was evaluated in 13/17 (76%) studies. We found published literature was scant on this topic despite warning signs of pandemic of a respiratory illness over the years. Promising technologies requiring expeditious evaluation are UVGI, Microwave generated steam (MGS) and based on Hydrogen peroxide vapor. Global presence of technologies, which have been given Emergency use authorisation for N95-FFR reprocessing, is extremely limited. Reprocessing of N95-FFRs by MGS should be considered for emergency implementation in resource limited settings to tackle shortage of N95-FFRs. Systematic review identifier PROSPERO, PROSPERO ID: CRD42020189684, (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020189684).

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Vincent, Richard L., Stephen N. Rudnick, James J. McDevitt, and Frances R. Wallach. "Toward a Test Protocol for Surface Decontamination Using a Mobile Whole‐room UVGI Device †." Photochemistry and Photobiology 97, no. 3 (April 21, 2021): 552–59. http://dx.doi.org/10.1111/php.13416.

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Bang, Jong-Il, Sueng-Jae Lee, Eun-Young Jung, Eun-Tack Lee, Seong-Ho Ji, and Minki Sung. "Prediction of Infection Reduction Effect for UVGI on the Under Floor Air Distribution System." Journal of The Korean Society of Living Environmental System 29, no. 2 (April 30, 2022): 111–21. http://dx.doi.org/10.21086/ksles.2022.4.29.2.111.

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Al-Rawi, Mohammad, Annette Lazonby, and Callan Smith. "Prototyping a low-cost residential air quality device using ultraviolet germicidal irradiation (UVGI) light." HardwareX 11 (April 2022): e00251. http://dx.doi.org/10.1016/j.ohx.2021.e00251.

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Scarpino, P. V., N. J. Jensen, P. A. Jensen, and R. Ward. "The use of ultraviolet germicidal irradiation (UVGI) in disinfection of airborne bacteria and rhinoviruses." Journal of Aerosol Science 29 (September 1998): S777—S778. http://dx.doi.org/10.1016/s0021-8502(98)90571-7.

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Lindsley, William G., Stephen B. Martin, Robert E. Thewlis, Khachatur Sarkisian, Julian O. Nwoko, Kenneth R. Mead, and John D. Noti. "Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity." Journal of Occupational and Environmental Hygiene 12, no. 8 (July 2015): 509–17. http://dx.doi.org/10.1080/15459624.2015.1018518.

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Jelden, Katelyn C., Shawn G. Gibbs, Philip W. Smith, Angela L. Hewlett, Peter C. Iwen, Kendra K. Schmid, and John J. Lowe. "Comparison of hospital room surface disinfection using a novel ultraviolet germicidal irradiation (UVGI) generator." Journal of Occupational and Environmental Hygiene 13, no. 9 (July 15, 2016): 690–98. http://dx.doi.org/10.1080/15459624.2016.1166369.

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Lindsley, William G., Tia L. McClelland, Dylan T. Neu, Stephen B. Martin, Kenneth R. Mead, Robert E. Thewlis, and John D. Noti. "Ambulance disinfection using Ultraviolet Germicidal Irradiation (UVGI): Effects of fixture location and surface reflectivity." Journal of Occupational and Environmental Hygiene 15, no. 1 (December 28, 2017): 1–12. http://dx.doi.org/10.1080/15459624.2017.1376067.

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McCreesh, Nicky, Aaron S. Karat, Kathy Baisley, Karin Diaconu, Fiammetta Bozzani, Indira Govender, Peter Beckwith, et al. "Modelling the effect of infection prevention and control measures on rate of Mycobacterium tuberculosis transmission to clinic attendees in primary health clinics in South Africa." BMJ Global Health 6, no. 10 (October 2021): e007124. http://dx.doi.org/10.1136/bmjgh-2021-007124.

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BackgroundElevated rates of tuberculosis in healthcare workers demonstrate the high rate of Mycobacterium tuberculosis (Mtb) transmission in health facilities in high-burden settings. In the context of a project taking a whole systems approach to tuberculosis infection prevention and control (IPC), we aimed to evaluate the potential impact of conventional and novel IPC measures on Mtb transmission to patients and other clinic attendees.MethodsAn individual-based model of patient movements through clinics, ventilation in waiting areas, and Mtb transmission was developed, and parameterised using empirical data from eight clinics in two provinces in South Africa. Seven interventions—codeveloped with health professionals and policy-makers—were simulated: (1) queue management systems with outdoor waiting areas, (2) ultraviolet germicidal irradiation (UVGI) systems, (3) appointment systems, (4) opening windows and doors, (5) surgical mask wearing by clinic attendees, (6) simple clinic retrofits and (7) increased coverage of long antiretroviral therapy prescriptions and community medicine collection points through the Central Chronic Medicine Dispensing and Distribution (CCMDD) service.ResultsIn the model, (1) outdoor waiting areas reduced the transmission to clinic attendees by 83% (IQR 76%–88%), (2) UVGI by 77% (IQR 64%–85%), (3) appointment systems by 62% (IQR 45%–75%), (4) opening windows and doors by 55% (IQR 25%–72%), (5) masks by 47% (IQR 42%–50%), (6) clinic retrofits by 45% (IQR 16%–64%) and (7) increasing the coverage of CCMDD by 22% (IQR 12%–32%).ConclusionsThe majority of the interventions achieved median reductions in the rate of transmission to clinic attendees of at least 45%, meaning that a range of highly effective intervention options are available, that can be tailored to the local context. Measures that are not traditionally considered to be IPC interventions, such as appointment systems, may be as effective as more traditional IPC measures, such as mask wearing.

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Journal articles on the topic 'UVGI'

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