An ultraviolet area sterilizer (UVAS) is mobile or stationary. The UVAS is positioned in a room, such an operating room or intensive care unit. Motion detectors sense movement, to assure that personnel have evacuated the space to be sterilized. Subsequently, UV-C generators, such as a bank of mercury bulbs, generate intense levels of UV-C. An array of multiple UV-C sensors scans the room, and determines the darkest area, or the area reflecting the lowest level of UV-C back to the sensors. A Microcontroller contained in the device calculates the time required to obtain a bactericidal dose of UV-C reflected back from darkest area. Once a bactericidal dose has been reflected to all the sensors, the unit notifies the operator and shuts down. By relying on reflected doses rather than direct exposure, the UVAS is able to sterilize or sanitize all surfaces within the room that are within view of an exposed wall or ceiling.
