Determination of the UV Inactivation Constant Under 280 nm UV LED Irradiation for SARS‐CoV‐2

• Published in: Photochemistry and photobiology Vol. 99; no. 1; pp. 101 - 105
• Main Authors: Biffi, Silvia, Signorini, Lucia, Cattaneo, Luciano, Della Corna, Lorenzo, Guercilena, Andrea, D’Alessandro, Sarah, Ferrante, Pasquale, Delbue, Serena
• Format: Journal Article
• Language: English
• Published: United States John Wiley and Sons Inc 01-01-2023
• Subjects: COVID-19 - prevention & control; Disinfection - methods; Humans; Pandemics - prevention & control; SARS-CoV-2; Ultraviolet Rays; Virus Inactivation - radiation effects
• ISSN: 0031-8655; 1751-1097; 1751-1097
• DOI: 10.1111/php.13653

ABSTRACT
The ongoing emergency provoked by the SARS‐CoV‐2 pandemic demands the development of technologies to mitigate the spread of infection, and UV irradiation is a technique that can efficiently address this issue. However, proper use of UV equipment for disinfection requires an understanding of how the effects on SARS‐CoV‐2 are dependent on certain parameters. In this work, we determined the UV‐C inactivation constant k for SARS‐CoV‐2 using an LED source at λ = 280 nm. Specifically, a Log3 reduction was measured after irradiation for 24 min with a delivered UV‐C dose of 23 J m−2. By multitarget model fitting, n = 2 and k = 0.32 ± 0.02 m2 J−1 were obtained. A lag time for the inactivation effect was also observed, which was attributed to the low irradiation levels used to perform the study. The combination of k and delay time allows for reliable estimation of disinfection times in small, closed environments.
The ongoing SARS‐CoV‐2 sanitary emergency demands the development of technologies to mitigate the spread of infection. UV irradiation can address this purpose. UV‐C inactivation constant k was determined using an LED source at ʎ = 280 nm. A Log3 reduction was measured after irradiation for 24 min (delivered UV‐C dose of 23 J m−2). By fitting with the multitarget model, n = 2 and k = 0.32 ± 0.02 m2 J−1 were obtained. A lag time in the inactivation effect was also observed, which was attributed to the low irradiation levels used. The combination of k and delay time allows reliable estimation of disinfection times in any environment.