The anti-microbial properties of UV-C light [Ultraviolet light - C band] are well known to scientists and have been used since the 1930's to kill germs containing DNA and RNA including bacteria, viruses, fungi and mold. UV-C light is invisible to the human eye.

It is at a higher frequency than UV-B light used in tanning salons. While UV-C is invisible, given sufficient intensity and exposure, it can kill most of the germs responsible for causing diseases in humans and animals. UV-C works by destroying the DNA and RNA [genetic material] of pathogens [disease causing bacteria, viruses, mold, etc.]. Once the DNA in a pathogen has been destroyed, the microorganism is either killed or deactivated, it can no longer function properly, it can no longer reproduce.