In the link below, the Centre for Disease Control and Prevention (CDC) in the United States recommends upper air disinfection as a method to combat Covid-19.
Upper Air disinfection was originally used in the 1940’s to fight off tuberculosis outbreaks in education environments. It was effective then and since, has been proven to be effective against the majority of all known airborne bacteria and viruses.
https://www.cdc.gov/coronavirus/2019-ncov/community/ventilation/uvgi.html
