Cumulative effects from repeated exposures to suberythemal doses of UVB and UVA in human skin

An estimation of biological hazards due to solar radiation

“…The erythemal UVA contribution found in this research is still significant with regards to skin damage as previous research [18] has found that repeated exposures to suberythemal doses of UVA induce human skin damage. On the other hand, the high relative contribution of the UVA waveband to fish melanoma indicate the possibility that the UVA waveband may contribute to human melanoma.…”

Ultraviolet Light Induced Alteration to the Skin

“…Membrane lipid damage caused by UVA-induced ROS, results in the release of arachidonic acid (AA) and this leads to altered membrane fluidity and activation of secondary cytosolic and nuclear messengers that activate UV-response genes 20,26 . Human skin exposed daily for 1 month to sub-erythemic UVA dose demonstrated epidermal hyperplasia, stratum corneum thickening, Langerhans cell depletion and dermal inflammatory infiltrates with deposition of lysozymes on the elastic fibers 31 . These changes suggest that even casual exposure to sunlight while wearing a UVB-absorbing sunscreen may eventually result in damage to dermal collagen and elastin in ways expected to produce photoaging …”

Dosimeter based on 8-methoxypsoralen for UVA exposures over extended periods

“…This was the boundary used in this research to define the UVA waveband although the wavelength boundary between the UVB and UVA is defined at both 315 nm and 320 nm. The CIE [27] defines the boundary as 315 nm; however 320 nm is employed in a significant number of publications, due largely to the biological significance of wavelengths between 315 and 320 nm [28,29]. …”