This could be useful.
https://www.dailymail.co.uk/sciencetech/article-10643177/New-type-UV-light-kills-98-microbes-room-help-prevent-pandemic.html
Z.
And that we have been doing for years, both for air and for drinking water from private wells. This short history of UV disinfection suggests the late 1800s as being pretty much the start https://www.uvtglobal.com/what-is-uv-c/the-history-of-uv-c/?v=79cba1185463
Mike.
