Erythemal effective UV dose
The erythemal effective UV dose (in German: sonnenbrandwirksame UV-Tagesdosis) is the total amount of erythemal effective UV radiation added up over the day. The minimal erythema dose (MED) is the dose (= energy) that leads to a slight sunburn (erythema) in a non-pre-tanned person of a certain skin type. Knowing the skin type and the current UV irradiance one can roughly estimate the time after which sunburn can occur. The unit of the erythemal effective UV dose is power per area times time, corresponding to energy per area, i.e. J/m². On the X axis the time ME(S)Z means Central European (Summer) Time CE(S)T.