Protection of skin against full solar, visible and infrared radiation by fabrics:
new testing methodology and perspective
The developed testing methodology is capable to measure fabrics protection potential against full solar spectrum irradiation and its VIS+ IR portion; it could be applied, in addition to UPF, to comprehensively evaluate sun protective fabrics. This methodology was utilized in comparative evaluation of various sun protective fabrics to determine their ability to provide protection beyond UV. It was demonstrated that fabrics are capable to effectively protect skin from full solar radiation and its VIS + IR portion and could contribute to novel strategies to help prevent skin photoaging.
According to CIE (Commission Internationale de l’Eclairage) the spectral distribution of natural solar radiation at earth surface contains ~ 7 percent of Ultraviolet light (UV) consisting of UVB (290-320 nm) and UVA (320-400 nm), ~ 55 percent of Visible light (VIS) from 400 to 780 nm, and ~ 40 percent Infrared light (IR) from 780 nm to 1 mm. (1-3). The damaging effects of UV radiation on skin are well-known. However, more than 90 percent of full solar radiation spectrum is in the VIS - IR range, and its potential contribution to skin damage is being increasingly recognized and actively evaluated. For example, Cho et al. indicated that in addition to UV radiation, VIS, IR plus heat energy generated by sunlight exposure induce MMP-1 expression in human skin. (4) Zastrow et al. demonstrated that the free radical formation is occurring in epidermis and dermis at UV, VIS and near-IR wavelengths; with fifty percent of the total skin oxidative burden being induced by VIS light. (5-6) The contribution of VIS to solar urticarial and porphyria cases, and the predominance of UVA and/or VIS in elicitation of photosensitivity conditions was noted by Me ...