Using light to fight the virus

Can ultraviolet light be used to fight the coronavirus in schools and other shared, indoor spaces? Agroup of researchers from Spain argues that it’s not a new idea, but a very logical one. Schools will be open in Connecticut this fall — assuming the trend continues— with some significant modifications. Masks will be worn, there might be smaller classes, fewer days a week in person and lots of disinfectant. It’s that last part with which a group of scientists from Barcelona are concerned. They argue that some bandwidths of ultraviolet light, which has been used to disinfect surfaces in hospitals for years and is effective against COVID- 19, should be used in schools and other shared spaces. “Among the available alternatives, UV- C light satisfies the requirements of rapid, widespread, and economically viable deployment,” they wrote. “With filters and chemicals requiring long- term planning and/ or the evacuation of people while in use, certain wavelengths of UV- C light emerge as the most promising solution to act swiftly on the SARSCoV- 2 pandemic because UV- C light meets the aforementioned requirements of fast, scalable, and affordable implementation.” Imagine, if you will, UVlight sources placed in air ducts or in bathrooms, hallways and other places where diseases like COVID- 19 are known to spread. “Disinfection of small confined spaces such as toilets and elevators could be achieved by shining UV- C light while they are not in use, requiring an illumination power inversely proportional to the dwell time between uses,” the study says. The problem is production. HowmanyUV light sources would you need for the strategy to actually have an effect on a large scale? More than we have available. Researchers wrote that “a global capital investment of a few billion dollars” could protect a billion people, students, workers, residents of large buildings. “However, the global market for UV- C light barely reaches $ 1 billion dollars per year currently, so it may have difficulty coping with the expected rise in demand originated by the SARS- CoV- 2 pandemic.”