A light tube apparatus includes a tubular housing, a first light source, a second light source, a driver and a controller. The tubular housing having a first light passing window and a second light passing window. The first light source is for emitting a white light from the first light passing window in an illuminating mode. The second light source is for emitting an ultraviolet light from the second light passing window in a sanitizing mode. The driver is for converting an external power source to a first driving current to the first light source and a second driving current to the second light source. The controller is for determining when to enter the sanitizing mode or the illuminating mode based on a stored criterion.