Determination of the UV Inactivation Constant Under 280 Nm UV LED Irradiation for SARS-CoV-2

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 lambda = 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 m(2) 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.