UVC LED Irradiation Effectively Inactivates Aerosolized Viruses, Bacteria, and Fungi in a Chamber-Type Air Disinfection System

Abstract

In this study, the possibility of inactivating viral, bacterial, and fungal aerosols in a chamber-type air disinfection system by using a UVC light-emittingdiode (LED) array was investigated and inactivation rate constants of each microorganism were calculated in fitting curves of surviving populations. UVC LED array treatment effectively inactivated viral infectivity, achieving 5-log reductions within 45 mJ/cm 2 for MS2, Q␤, and X174 viruses. UVC LED array effectiveness in inactivating Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Staphylococcus aureus aerosols achieved 2.5-to 4-log reductions within 1.5 to 4.6 mJ/cm 2 . Also, 4-log reductions of Aspergillus flavus and Alternaria japonica were achieved at a dosage of 23 mJ/cm 2 using UVC LED array irradiation. The highest UV susceptibility, represented by the inactivation rate constant, was calculated for bacteria, followed by fungi and viruses. UVC LED, an innovative technology, can effectively inactivate microorganisms regardless of taxonomic classification and can sufficiently substitute for conventional mercury UV lamps. IMPORTANCE The United Nations Environment Programme (UNEP) convened the Minamata Convention on Mercury in 2013 to ban mercury-containing products in order to ensure human and environmental health. It will be effectuated in 2020 to discontinue use of low-pressure mercury lamps and new UV-emitting sources have to replace this conventional technology. However, the UV germicidal irradiation (UVGI) system still uses conventional UV lamps, and no research has been conducted for air disinfection using UVC LEDs. The research reported here investigated the inactivation effect of aerosolized microorganisms, including viruses, bacteria, and fungi, with an UVC LED module. The results can be utilized as a primary database to replace conventional UV lamps with UVC LEDs, a novel type of UV emitter. Implementation of UVC LED technology is truly expected to significantly reduce the extent of global mercury contamination, and this study provides important baseline data to help ensure a healthier environment and increased health for humanity.

Rapid inactivation of SARS-CoV-2 with deep-UV LED irradiation

“…A deep ultraviolet light-emitting diode (DUV-LED) instrument generating around 250-300 nm wavelength has been reported to effectively inactivate microorganisms, including bacteria, viruses and fungi [8][9][10][11], but effects on SARS-CoV-2 have not been reported. We evaluated the antiviral efficacy of irradiation by DUV-LED, generating a narrow-range wavelength (280 ± 5 nm, mean ± SD) (Nikkiso Co., Tokyo, Japan), which we tested against SARS-CoV-2.…”

Sanitization During and After COVID-19 Pandemic: A Short Review

“…The effect of ultraviolet germicidal irradiation to inactivate surface viruses were demonstrated. Kim and Kang ( 2018 ) measured the effectiveness of UVC LED in inactivating viruses. Moore in an article in ieeespectrum (dated 16th April 2020) explains how UVC LED makers claim to eliminate corona virus using a 30 s dose from a 3 cm distance.…”

Combined ohmic heating and krypton‐chlorine excilamp treatment for the inactivation of Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 in apple juice

“…Excimer lamps and light emitting diodes are representative methods for generating UV radiation without mercury (D.‐K. Kim & Kang, ). In particular, application of 222‐nm krypton‐chlorine (KrCl) excilamps for inactivation of foodborne pathogens has been of interest recently because their bactericidal efficacy is known to superior to that of LP Hg lamps (Ha, Lee, & Kang, ).…”