Evaluation of the antimicrobial effect of a far-uv radiation lamp in a real-life environment.

Background: Using far-Ultraviolet-C (UVC) radiation with an emission maximum of 222 nm, has the potential to kill bacteria while not being harmful to humans and can be used continuously in public areas. Elevators pose a high risk of infection transmission, as they are small, crowded spaces with poor ventilation. In such a setting continuous decontamination would be very useful. This study aimed to measure the effectiveness of a far-UVC lamp installed in a frequently used elevator by comparing the bacterial load found in that elevator with the bacterial load in a control elevator. Methods: Microbial load was measured by different methods; ATP bioluminescence, surface samples were collected by contact slides, contact plates, and swabbing. Air samples were also collected. Results: No significant differences were found in the microbial content between the control elevator and the UV-lamp elevator, regardless of whether the UV-lamp was always on, or was used with a motion sensor to turn off when someone entered the elevator. Conclusions: The results suggest that the far-UVC requires a longer time to kill the bacteria, while the people traffic were continuously re-contaminating the elevators.