Further insights on the antimicrobial effectiveness of far-UVC light

The anti-microbial capacity of far-ultraviolet C (UVC) light (200-235 nm) has been shown for a variety of pathogens. There is evidence that far-UVC has limited ability to damage human skin and eyes; therefore, far-UVC fixtures could be used to continuously disinfect occupied indoor spaces and be a practical intervention for pandemic control. Our group has previously shown that 222 nm inactivated aerosolized viruses as well as drug-resistant bacteria when exposed on agar surfaces or in aerosol. This work extends those studies and presents novel findings from a series of experiments conducted over the past five years, all aimed at probing different aspects of the antimicrobial effectiveness of far-UVC light. Specifically, the study (1) describes the susceptibility of human coronavirus OC43 (HCoV OC43) exposed on a plastic surface to different sources of far-UVC; (2) describes the survival of clinical bacterial isolates exposed to 222 nm on agar surfaces; (3) evaluates a suitable surrogate of human viruses exposed to 222 nm in aerosol; (4) compares the inactivation of HCoV OC43 exposed to 222 nm on surfaces, aerosol, or in aqueous solution. By integrating complementary observations, the results contribute further evidence supporting the effectiveness of far-UVC against pathogens exposed under different laboratory conditions.