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. Author manuscript; available in PMC: 2019 Feb 14.
Published in final edited form as: Photochem Photobiol Sci. 2018 Feb 14;17(2):127–179. doi: 10.1039/c7pp90043k

Fig. 4.

Fig. 4

The graph shows the effectiveness of sunscreen of different sun protection factors (SPF) for preventing sunburn. The dose of UV radiation (x-axis) is presented in units of the dose that will cause minimal erythema (MED) of the skin. The y-axis is the percentage of a sunburning dose (1 MED) that will be received by the skin, using sunscreens of different SPF. With no sunscreen (SPF = 1) a dose of UV radiation of 1 MED results in 100% of the dose required to cause sunburn. With successively higher SPF sunscreens, the dose of UV radiation required to reach 1 MED (100% of a sunburning dose) increases. Adapted from ref. 106.