The SUV-E measures according to ISO 17166:1999 and CIE/S 007/E-1999 the erythemally active UV radiation that causes harm to human skin. It converts the irradiance in W/m2 into the UV Index for public health information.
Ultraviolet (UV) radiation is part of the Sun’s light spectrum that reaches the earth. UV radiation breaks down into wavelengths that are invisible to the naked eye. There are three types of UV rays: UVA, UVB and UVC. They decrease in length from A to C but increase in intensity, meaning that the shorter the wavelength, the more potential for damage. Fortunately, only UVA and UVB rays can penetrate the earth’s atmosphere.