The virus that causes COVID-19 can be killed with a particular wavelength of ultraviolet (UV) light, but recent study from the University of Colorado Boulder shows that UV light of this wavelength is also safer to use in public places. Published in Applied and Environmental Microbiology this month, the research examines how various UV light wavelengths affect SARS-CoV-2 and other respiratory viruses for the first time, including the only UV light wavelength to which live beings may be exposed without protection. The study. Findings that the authors call “game changers” may lead to new low-cost and highly successful methods of decreasing viral transmission in crowded public places like airports and concert halls, which are notoriously difficult to keep clean and germ-free.
Karl Linden, a professor of environmental engineering and the study’s senior author, said of the virus: “It is one of the simplest pathogens we have ever examined, by far. “It just requires a little dosage to have an effect. As a result, UV technology seems to be a promising option for safeguarding public areas.” Even while the sun naturally emits UV radiation, the majority of it is detrimental to humans, animals, and microbes like viruses. In the genome of an organism, this light may bind and inhibit reproduction by tying together DNA strands. However, the ozone layer prevents these damaging solar wavelengths from reaching the Earth’s surface. Fluorescent tube lights, for example, utilize UV light that has been humanly designed, but the rays are shielded by an inner layer of white phosphorous.
Because of this, taking the covering off exposes us to these damaging wavelengths, but they may also be used to destroy infections, according to Linden. Even when there are no patients present, hospitals employ UV light technology to disinfect surfaces in operating rooms and patient rooms by shining UV light on them between usage. UV light is used in numerous consumer electronics products today, from mobile phones to water bottles. The FDA and EPA, on the other hand, are still working on safety standards. When it comes to personal or “germicidal” devices, Linden warns against utilizing those that expose a person to UV radiation. It’s the first time such discoveries have been made, according to him, since they strike the sweet spot between UV radiation that’s harmless for people but damaging to viruses, particularly the one that causes COVID-19.
Linden and his colleagues used standardized techniques established throughout the UV light industry to evaluate various UV wavelengths side by side for the research. SARS-CoV-2 must be killed by UV radiation, according to Linden. “We thought, let’s get together and make a definite declaration on that,” he added. For this reason, we wanted to make sure that if UV light is being used to combat illness, it is doing so in a way that is both safe for people’s health and kind on their skin at the same time. Working with SARS-CoV-2 requires very strict safety standards, therefore opportunities to conduct this kind of work are quite uncommon. The University of Arizona’s Charles Gerba Virology Laboratory, where the virus and its variations were allowed to be studied, hosted Linden and postdoctoral researcher Ben Ma of Linden’s research group.
Far ultraviolet-C light with a wavelength of 222 nanometers was especially efficient in killing the virus, the researchers discovered. High-intensity krypton chloride excimer lamps produce this intense wavelength, which is powered by molecules shifting between various energy levels. With the ability to destroy viral proteins and nucleic acids much higher than conventional UV-C devices, as well as being blocked by the top layers of human skin and eyes — this means that at dosages capable of wiping out viruses, it has little to no adverse health consequences. Since the early twentieth century, UV radiation has been extensively utilized to disinfect water, air, and surfaces in different ways. In hospitals and schools, it has been used since the 1940s to prevent the spread of TB by disinfecting the air as it circulates around the space. When there are no patients present, it’s utilized not just in hospitals, but also in certain public restrooms and on aircraft as well. An accompanying White Paper by the International UV Association, “Far UV-C Radiation: Current State of Knowledge,” asserts, among other things, that this safer wavelength of Far UV-C light could be a key mitigation measure against current and future pandemics, in addition to improved ventilation, mask wearing and vaccination. Linden is one of the authors of this paper.
It’s possible that Linden’s air disinfection systems could either be designed to run continuously in indoor spaces to keep the air and surfaces clean or to be hidden behind a social barrier that separates students from teachers, customers from service providers, and people in places where social distancing is not possible. As an alternative to greater ventilation, UV light disinfection may provide protection equal to increased air changes per hour inside a room. Installing UV lamps is also a lot less expensive than upgrading your HVAC system as a whole. “Saving money and energy while also preserving public health is possible in this situation. The anticipation is palpable, “said Linden with a smile.
Reference : Ben Ma, Patricia M. Gundy, Charles P. Gerba, Mark D. Sobsey, Karl G. Linden. UV Inactivation of SARS-CoV-2 across the UVC spectrum: KrCl* excimer, mercury-vapor, and LED sources. Applied and Environmental Microbiology, 2021; DOI: 10.1128/AEM.01532-21