[Absorption and dispersion of ultraviolet radiation in human skin]

The study was carried out in a group composed of 48 men. The linear coefficient and linear coefficient of dispersion of ultraviolet radiation (UVR) in the skin was measured for different wavelengths. The mean values were determined for four types of the skin in both ultraviolet A (UVA) and ultraviolet B (UVB) ranges from 280 to 400 nm. The skin ability to absorb UVR decreases rapidly with decreasing wavelength. At wavelength of 280 nm, the coefficient of absorption changed within the range from 105 cm-1 (skin type II) to 160 cm-1 (skin type V), however, at wavelength of 400 nm it accounted only for 20 cm-1. A reciprocal relationship for scattering was found. The coefficient of dispersion changed within the range from 3.5 cm-1 at wavelength of 280 nm to 12 cm-1 at wavelength of 400nm. The mechanism based on absorption predominated at a shorter wave range (UVB), while at a longer range (UVA) the scattering mechanism was more efficient.