Lighting The Way to Minimizing the Future Spread of Covid

 by: Ruby Ayala

Disinfection through the traditional use of chemicals (pictured on the left) vs disinfection through the use of UV light (pictured on the right).    Photo Credit: Jennifer M. Mccan/Penn State

With the ongoing cases of covid-19 in today's society, scientists are looking for ways to minimize the spread of the virus. One proposed method of disinfection is through the use of ultraviolet (UV) light radiation, which has been proven to be an effective tool in killing viruses. In fact, UV light technology has already been adopted to use for disinfection purposes in healthcare settings. however, due to the safety testing requirements of SARS-CoV-2 being limited to biosafety level 3 laboratories, data on the efficiency of UV light on covid disinfection is still limited. In a study by Ben Ma et al., they researched the effects of different far ultraviolet-C light wavelengths on the SARS-CoV-2 virus, as well as identified the murine hepatitis virus, which falls under a lower biosafety level, as a reliable substitution for covid-19 in further UV disinfection tests. For this study, virus samples were diluted in thin-film liquid and placed under the following five UV sources: a filtered KrCl excimer UV light, an unfiltered KrCl excimer light, a mercury UV lamp, and two UV LED systems. The results showed that all the UV lights were capable of inactivating the virus in the aqueous solution; however, both the krypton chlorine (KrCl) excimer UV lights produced the highest disinfection rates. Compared to the other far ultraviolet-C devices, the krypton chloride excimer lamp is fueled by molecules moving between different states of energy, so a UV wavelength at 222 nanometers is able to inflict greater viral protein and nucleic acid damage to the virus due to the wavelength's high energy. This finding is particularly important because this ultraviolet-C device is relatively safe for human exposure, thus it can be used in occupied public spaces, such as subways and elevators, to disinfect viruses in airborne droplets and contaminated surfaces. 

Original Article:

Ma, B., Gundy, P.M., Gerba, C. P., Sobsey, M. D., & Linden, K. G. (2021). UV Inactivation of SARS-CoV-2 across the UVC spectrum: KrCl* excimer, mercury-vapor, and LED sources. Applied and environmental microbiology, AEM0153221. Advance online publication. https://doi.org/10.1128/AEM.01532-21