UV-Based Technologies for SARS-CoV2 Inactivation: Status and Perspectives

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent of COVID-19, which has affected the international healthcare systems since the beginning of 2020. Among sanitizing approaches, UV irradiation is a well-known technology often used in different environments to reduce the microbial contamination and the viral transmission. In particular, several works have demonstrated that UVC radiation is able to inactivate SARS-CoV-2 compromising its viral genome and virion integrity. With this work we review and analyze the current status of the pandemic and the state of the art of the UV technology. With traditional UVC discharge lamps having a serious environmental issue, due to their working principle based on mercury, a primary focus is shifted on the aluminum gallium nitride based deep-ultraviolet light emitting diodes. These devices are exploited for compact and environmentally friendly disinfection systems, but efficiency and reliability still play a limiting role into their mass market adoption and system efficacy. In this work we then analyze the latest reports on the effects of dose and wavelength on viral inactivation, thus providing two key pillars for the development of UVC based disinfection systems: the status of the technology and a quantitative evaluation of the dose required to achieve an effective coronavirus inactivation.

The effectiveness of commercial household ultraviolet C germicidal devices in Thailand

“…The emission spectra of 3 studied LEDs were described in Table 1 . Although luminous efficiencies were not given by manufacturers, the efficiency of UVC-LED varies from 1 to 3%, which is significantly lower compared to those of LPML 12 , 13 . As can be expected, no turn-time was required in 3 studied UVC-LEDs, which are evidently shown in Supplementary Fig.…”

“…First is the type of UVC light source. As mentioned, commercially available UVC devices could be categorized into LPML and LED 12 , 13 . LPML, or UVC discharge lamp, is a traditional UVC source mainly emitting at 253.7 nm for more than 90% of their total spectral power.…”

“…Other important drawbacks include limited lifetime and turn-on time. To reach the expected output power, LPML usually requires few seconds to some minutes for preheating 12 . Regarding 7 LPMLs included in this study, their turn-on time ranged from 1 to 300 s (see Supplementary Fig.…”

“…With its nontoxicity, compactness, and instant turn-on compensation, the popularity of UVC-LED has been gradually rising. However, low external quantum efficiency, aging of the packaging material, and thermal management problems are the main faults 12 , 13 , 18 . A LED is a semiconductor light source that emits a particular wavelength of light depending on semiconductor material and its structure.…”

“…Commercially available UVC devices could be categorized into 2 main types based on type of UVC light source which are low-pressure mercury lamp (LPML) and light-emitting diode (LED). A wide range of applications were developed and introduced to be favorable for household-use purpose 12 , 13 . To the best of our knowledge, no study has evaluated the effectiveness of commercial household UVC devices for SARS-CoV-2 inactivation.…”