scholarly journals Bare‐bulb Upper‐Room Germicidal Ultraviolet‐C (GUV) Indoor Air Disinfection for COVID‐19 †

2021 ◽  
Author(s):  
Bruce L. Davidson
Keyword(s):  
Indoor Air ◽  
Ultraviolet C ◽  
Air Disinfection ◽  
Upper Room

scholarly journals Characterization of UVC Light Sensitivity of Vaccinia Virus

2007 ◽  
Vol 73 (18) ◽  
pp. 5760-5766 ◽  
Author(s):  
James J. McDevitt ◽  
Ka Man Lai ◽  
Stephen N. Rudnick ◽  
E. Andres Houseman ◽  
Melvin W. First ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Light Sensitivity ◽  
Scientific Basis ◽  
Smallpox Virus ◽  
Virus Susceptibility ◽  
Public Health Authorities ◽  
Air Disinfection ◽  
Log Normal ◽  
The Impact ◽  
Upper Room

ABSTRACT Interest in airborne smallpox transmission has been renewed because of concerns regarding the potential use of smallpox virus as a biothreat agent. Air disinfection via upper-room 254-nm germicidal UV (UVC) light in public buildings may reduce the impact of primary agent releases, prevent secondary airborne transmission, and be effective prior to the time when public health authorities are aware of a smallpox outbreak. We characterized the susceptibility of vaccinia virus aerosols, as a surrogate for smallpox, to UVC light by using a benchtop, one-pass aerosol chamber. We evaluated virus susceptibility to UVC doses ranging from 0.1 to 3.2 J/m2, three relative humidity (RH) levels (20%, 60%, and 80%), and suspensions of virus in either water or synthetic respiratory fluid. Dose-response plots show that vaccinia virus susceptibility increased with decreasing RH. These plots also show a significant nonlinear component and a poor fit when using a first-order decay model but show a reasonable fit when we assume that virus susceptibility follows a log-normal distribution. The overall effects of RH (P < 0.0001) and the suspending medium (P = 0.014) were statistically significant. When controlling for the suspending medium, the RH remained a significant factor (P < 0.0001) and the effect of the suspending medium was significant overall (P < 0.0001) after controlling for RH. Virus susceptibility did not appear to be a function of virus particle size. This work provides an essential scientific basis for the design of effective upper-room UVC installations for the prevention of airborne infection transmission of smallpox virus by characterizing the susceptibility of an important orthopoxvirus to UVC exposure.

A design for a more efficient, upper room germicidal ultraviolet air disinfection luminaire

2017 ◽  
Vol 49 (6) ◽  
pp. 788-799 ◽  
Author(s):  
S Milonova ◽  
HM Brandston ◽  
S Rudnick ◽  
P Ngai ◽  
K Simonson ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Real World ◽  
Design Principle ◽  
Optical Design ◽  
Real World Application ◽  
Biological Effectiveness ◽  
Air Disinfection ◽  
Uv C ◽  
Upper Room

This paper describes a novel optical design principle for an upper room germicidal ultraviolet luminaire developed to limit the transmission of airborne diseases, particularly tuberculosis. A prototype was built to demonstrate the principle, and tests were conducted to determine its total ultraviolet (UV)-C output, biological effectiveness, and safety for lower room occupants. The prototype outperformed frequently used luminaires in total UV-C output, luminaire efficiency, and biological effectiveness against aerosolised Mycobacterium, while remaining safe for lower room occupants. The results presented here suggest that the design principle is ready for real-world application to mitigate the spread of airborne infectious diseases.

scholarly journals Upper-room ultraviolet air disinfection might help to reduce COVID-19 transmission in buildings

2020 ◽  
Author(s):  
Clive B. Beggs ◽  
Eldad J. Avital
Keyword(s):  
Feasibility Study ◽  
Published Data ◽  
Confined Space ◽  
Uv Damage ◽  
Worst Case ◽  
Confined Spaces ◽  
The World ◽  
Air Disinfection ◽  
Uv C ◽  
Upper Room

AbstractAs the world economies get out of the lockdown imposed by the COVID-19 pandemic, there is an urgent need to assess the suitability of known technologies to mitigate COVID-19 transmission in confined spaces such as buildings. This feasibility study looks at the method of upper-room ultraviolet (UV) air disinfection that has already proven its efficacy in preventing the transmission of airborne diseases such as measles and tuberculosis.Using published data from various sources it is shown that the SARS-CoV-2 virus, which causes COVID-19, is highly likely to be susceptible to UV damage while suspended in air irradiated by UV-C at levels that are acceptable and safe for upper-room applications. This is while humans are present in the room. Both the expected and worst-case scenarios are investigated to show the efficacy of the upper-room UV-C approach to reduce COVID-19 air transmission in a confined space with moderate but sufficient height. Discussion is given on the methods of analysis and the differences between virus susceptibility to UV-C when aerosolised or in liquid or on a surface.

scholarly journals Institutional Tuberculosis Transmission. Controlled Trial of Upper Room Ultraviolet Air Disinfection: A Basis for New Dosing Guidelines

2015 ◽  
Vol 192 (4) ◽  
pp. 477-484 ◽  
Author(s):  
Matsie Mphaphlele ◽  
Ashwin S. Dharmadhikari ◽  
Paul A. Jensen ◽  
Stephen N. Rudnick ◽  
Tobias H. van Reenen ◽  
...  
Keyword(s):  
Controlled Trial ◽  
Tuberculosis Transmission ◽  
Air Disinfection ◽  
Upper Room

scholarly journals Aerosol Susceptibility of Influenza Virus to UV-C Light

2012 ◽  
Vol 78 (6) ◽  
pp. 1666-1669 ◽  
Author(s):  
James J. McDevitt ◽  
Stephen N. Rudnick ◽  
Lewis J. Radonovich
Keyword(s):  
Influenza Virus ◽  
Relative Humidity ◽  
Influenza A ◽  
Virulent Strain ◽  
Airborne Transmission ◽  
Mortality And Morbidity ◽  
Virus Susceptibility ◽  
Air Disinfection ◽  
Uv C ◽  
Upper Room

ABSTRACTThe person-to-person transmission of influenza virus, especially in the event of a pandemic caused by a highly virulent strain of influenza, such as H5N1 avian influenza, is of great concern due to widespread mortality and morbidity. The consequences of seasonal influenza are also substantial. Because airborne transmission appears to play a role in the spread of influenza, public health interventions should focus on preventing or interrupting this process. Air disinfection via upper-room 254-nm germicidal UV (UV-C) light in public buildings may be able to reduce influenza transmission via the airborne route. We characterized the susceptibility of influenza A virus (H1N1, PR-8) aerosols to UV-C light using a benchtop chamber equipped with a UVC exposure window. We evaluated virus susceptibility to UV-C doses ranging from 4 to 12 J/m2at three relative humidity levels (25, 50, and 75%). Our data show that the Z values (susceptibility factors) were higher (more susceptible) to UV-C than what has been reported previously. Furthermore, dose-response plots showed that influenza virus susceptibility increases with decreasing relative humidity. This work provides an essential scientific basis for designing and utilizing effective upper-room UV-C light installations for the prevention of the airborne transmission of influenza by characterizing its susceptibility to UV-C.

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