Airborne-mediated microbial diseases such as infuenza and tuberculosis represent major public
health challenges. A direct approach to prevent airborne transmission is inactivation of airborne
pathogens, and the airborne antimicrobial potential of UVC ultraviolet light has long been established;
however, its widespread use in public settings is limited because conventional UVC light sources are
both carcinogenic and cataractogenic. By contrast, we have previously shown that far-UVC light
(207–222nm) efciently inactivates bacteria without harm to exposed mammalian skin. This is because,
due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer
(non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or
smaller dimensions, far-UVC can penetrate and inactivate them. We show for the frst time that far-UVC
efciently inactivates airborne aerosolized viruses, with a very low dose of 2mJ/cm2 of 222-nm light
inactivating >95% of aerosolized H1N1 infuenza virus. Continuous very low dose-rate far-UVC light
in indoor public locations is a promising, safe and inexpensive tool to reduce the spread of airbornemediated microbial diseases