A portable UV-C disinfection apparatus, method, and system for ultraviolet germicidal irradiation. UV-C emitters may be coupled to an array housing having a planar array surface in a vertical configuration. UV-C sensors are configured to measure the amount of UV-C light or near UV-C light from a target surface. A controller may be configured to engage with the UV-C sensors to determine the amount of UV-C radiation collected by the UV-C sensors. The controller includes instructions stored on a memory according to the amount of UV-C radiation collected corresponding to an effective kill-dose for surface disinfection. The improved apparatus, method, and system reduces exposure time by varying the intensity and wavelength of the UV-C administered, while concurrently reducing UV overexposure to surfaces by administering radiation through a rotational zonal application.
