UVI

A standardized index used worldwide that assigns a numerical value to the intensity of the ultraviolet radiation reaching the Earth's surface. It is calculated from a mathematical formula that integrates, over the range of the electromagnetic spectrum located between 250 and 400 nanometers, the product of the solar spectral irradiance (the radiant energy reaching us from the sun) by the so-called "reference action spectrum for erythema." The resulting number allows us to know what protective measures need to be taken to avoid skin damage from sun exposure. To calculate the UVI, measurements can be taken on the ground with a spectrophotometer and entered into the mathematical formula, or it can be determined using a calibrated broadband detector programmed for that purpose.