The role of UV and blue light in photo-eradication of microorganisms

Abstract: Photo-eradication of microorganisms with UV and blue light has been around since the 1870s. Research to further the development and deployment of germicidal UV and violet-blue light has been on the rise since COVID-19 pandemic. This paper traces the evolution of UV and violet-blue light, presents suggested ways to exploit two leading germicidal light technologies—far UV and pulsed blue light (PBL)—in the ongoing quest to effectively stem the spread of pandemic diseases. An effective way to overcome or minimize the spread of disease is to inactivate and reduce the number of viral particles both in the environment and in accessible parts of patients. This can be achieved by irradiating spaces, infected air, and the general environment with PBL or far UV, and by similarly disinfecting supplies, tools, and equipment. Irradiating the oronasal cavity of infected patients with PBL could clear the virus and kill oral opportunistic bacteria that worsen coronavirus infections. The advantages and disadvantages of the two-leading photo-disinfection light technologies are discussed