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

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.

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

10.1101/2020.06.12.20129254 ◽

2020 ◽

Cited By ~ 1

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.

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Aerosol Susceptibility of Influenza Virus to UV-C Light

Applied and Environmental Microbiology ◽

10.1128/aem.06960-11 ◽

2012 ◽

Vol 78 (6) ◽

pp. 1666-1669 ◽

Cited By ~ 46

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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Upper-room ultraviolet air disinfection might help to reduce COVID-19 transmission in buildings: a feasibility study

PeerJ ◽

10.7717/peerj.10196 ◽

2020 ◽

Vol 8 ◽

pp. e10196

Author(s):

Clive B. Beggs ◽

Eldad J. Avital

Keyword(s):

Feasibility Study ◽

Causative Agent ◽

Published Data ◽

Worst Case ◽

Confined Spaces ◽

Ceiling Height ◽

Air Disinfection ◽

Uv C ◽

Upper Room

As the world’s economies come out of the lockdown imposed by the COVID-19 pandemic, there is an urgent need for technologies to mitigate COVID-19 transmission in confined spaces such as buildings. This feasibility study looks at one such technology, upper-room ultraviolet (UV) air disinfection, that can be safely used while humans are present in the room space, and which has already proven its efficacy as an intervention to inhibit 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, the causative agent of COVID-19, is highly likely to be susceptible to UV-C damage when suspended in air, with a UV susceptibility constant likely to be in the region 0.377–0.590 m2/J, similar to that for other aerosolised coronaviruses. As such, the UV-C flux required to disinfect the virus is expected to be acceptable and safe for upper-room applications. Through analysis of expected and worst-case scenarios, the efficacy of the upper-room UV-C approach for reducing COVID-19 transmission in confined spaces (with moderate but sufficient ceiling height) is demonstrated. Furthermore, it is shown that with SARS-CoV-2, it should be possible to achieve high equivalent air change rates using upper-room UV air disinfection, suggesting that the technology might be particularly applicable to poorly ventilated spaces.

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