Abstract: Aspects described herein include methods, apparatuses, and non-transitory computer-readable storage mediums for operating a germicidal lighting device. A target environment is monitored for one or more people. In response to the monitoring indicating the presence of one or more people, the lighting device is caused to operate in an occupied target environment operating mode including causing the lighting device to emit far-UVC light at a given intensity into the target environment for a first period of time; and, in response to expiry of the first period of time, causing the lighting device to emit far-UVC light at a different intensity to the given intensity into the target environment for a second period of time.