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. 2022 Oct 4:10:875817.
doi: 10.3389/fbioe.2022.875817. eCollection 2022.

Ultraviolet dosage and decontamination efficacy were widely variable across 14 UV devices after testing a dried enveloped ribonucleic acid virus surrogate for SARS-CoV-2

Tony L Buhr  1 , Erica Borgers-Klonkowski  1 , Bradford W Gutting  1 , Emlyn E Hammer  1 , Shelia M Hamilton  1 , Brett M Huhman  2 , Stuart L Jackson  2 , Neil L Kennihan  1 , Samuel D Lilly  1 , John D Little Jr  2 , Brooke B Luck  1 , Emily A Matuczinski  1 , Charles T Miller  1 , Rachel E Sides  1 , Vanessa L Yates  1 , Alice A Young  1
Affiliations

Ultraviolet dosage and decontamination efficacy were widely variable across 14 UV devices after testing a dried enveloped ribonucleic acid virus surrogate for SARS-CoV-2

Tony L Buhr et al. Front Bioeng Biotechnol. .

Abstract

Aims: The dosages and efficacy of 14 ultraviolet (UV) decontamination technologies were measured against a SARS-CoV-2 surrogate virus that was dried onto different materials for laboratory and field testing. Methods and results: A live enveloped, ribonucleic acid (RNA) virus surrogate for SARS-CoV-2 was dried on stainless steel 304 (SS304), Navy Top Coat-painted SS304 (NTC), cardboard, polyurethane, polymethyl methacrylate (PMMA), and acrylonitrile butadiene styrene (ABS) materials at > 8.0 log10 plaque-forming units (PFU) per test coupon. The coupons were then exposed to UV radiation during both laboratory and field testing. Commercial and prototype UV-emitting devices were measured for efficacy: four handheld devices, three room/surface-disinfecting machines, five air disinfection devices, and two larger custom-made machines. UV device dosages ranged from 0.01 to 729 mJ cm-2. The antiviral efficacy among the different UV devices ranged from no decontamination up to nearly achieving sterilization. Importantly, cardboard required far greater dosage than SS304. Conclusion: Enormous variability in dosage and efficacy was measured among the different UV devices. Porous materials limit the utility of UV decontamination. Significance and impact of the study: UV devices have wide variability in dosages, efficacy, hazards, and UV output over time, indicating that each UV device needs independent technical measurement and assessment for product development prior to and during use.

Keywords: COVID-19; SARS-CoV-2; UV decontamination; decontamination; enveloped virus; enveloped virus Ф6; ultraviolet (UV).

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Φ6 extraction procedure for test samples and non-treated controls.
FIGURE 2
FIGURE 2
Normalized wavelength emission spectra for 14 UV devices. Top frame shows Xenex ( ) and pulsed xenon ( ) emission. Lower frame shows the emission for three 222 nm emitters ( ), eight 254 nm emitters ( ), and the 272 nm emitter ( ).
FIGURE 3
FIGURE 3
Testing setup and UV coverage for 18 and 35 W handheld devices. (A) GermAwayUV 18 W handheld device and custom test chamber shown during coupon exposure. (B) GermAwayUV 35 W handheld device and custom test chamber, shown in the pre/post exposure state. (C,D) UV coverage heat maps for the 18 W device (C) and the 35 W device (D) taken 5 cm from the source.
FIGURE 4
FIGURE 4
(A) Prototype 272 nm LED handheld inside the wooden test chamber. (B) UV coverage heat map taken 5 cm from the source.
FIGURE 5
FIGURE 5
(A) Prototype 222 nm Excimer Lamp Module Board inside the wooden test chamber. (B) UV coverage heat map taken 5 cm from the source.
FIGURE 6
FIGURE 6
Virus-inoculated coupons were placed 0.5, 1, or 2 m below the pulsed Xe prototype.
FIGURE 7
FIGURE 7
Virus-inoculated coupons were placed 1.78 m horizontally from the Xenex LightStrike or 2.63 m away from the LEM.
FIGURE 8
FIGURE 8
Dosimeters traveling down conveyor to determine exposure times for target UV dosages.
FIGURE 9
FIGURE 9
Prototype Big Box UV-C Chamber with a double-stacked pallet (top). Coupon placement was inside Petri plates on top of the pallet for testing (bottom).
See this image and copyright information in PMC

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