An apparatus and a method, in a handheld portable multi purpose device, for producing multiple and variable wavelength distributions of UV radiation, or visible radiation, comprising a primary UV radiation source, and a system of wavelength transforming (WT) materials that allows selecting at will between UV A, UV B, UV C radiation (individual selections or various combinations,) and visible radiation, whereby the apparatus provides for UV sterilization of food, fluid, air, fluids, and surfaces while also providing a means to emit visible light. Additionally, an apparatus and method, in a handheld portable multi purpose device, for enabling production and emission of UV radiation selectable between UV A, UV B, UV C radiation (individual selections or various combinations,) and visible radiation in a small form factor device embodied in a handheld portable flashlight, or lamp, type device.
