The ability of UV light to kill Covid-19 is well known. However, Tel Aviv University tests show UV with a wavelength of 285 nanometers kills 99.9% of the virus in 30 seconds – nearly as good as UV at 265nm. 285nm UV LED bulbs are cheaper and more readily available than 265nm.

https://unitedwithisrael.org/israeli-corona-discovery-uv-led-lights-kill-covid-19/