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Illustration of the limitations of current measures of sun protection. The solid curve shows the measured transmittance of Sunscreen B applied at 2 mg/cm2, which has a SPF rating of 50 but had a measured UPF of only 31. The dashed curve was generated using a shifting function to simulate a transmittance curve with an average UPF of 50. For both the measured and simulated curve, the rapid increase in transmittance in the UVA region represents reduced protection from UVA radiation.
