① The ultraviolet index is a value that quantifies the effect of ultraviolet radiation on the erythema (temporarily·locally redness of the skin) by applying the erythemal action spectrum as weighted function. ② Vitamin D synthesis index is a value that quantifies the effect of ultraviolet radiation on the production of vitamin D in human skin by applying the vitamin D action spectrum as weight function. ③ Plant response index is a value that quantifies the effect of ultraviolet radiation to plant response by applying the plant response action spectrum as weight function. ④ DNA damage index is a value that quantifies the effect of ultraviolet radiation to DNA damage by applying the DNA damage action spectrum as weight function.