Ultraviolet Exposure: Health Effects

Abstract

Ultraviolet radiation is part of the solar radiation spectrum. Every life on earth is affected by solar radiation and direct exposure is mostly unavoidable. Exposure to sun rays produce positive effects on humans, but there are also adverse effects that should be regarded. This article describes first the physical background in order to establish a basis for understanding the nature of electromagnetic radiation to which ultraviolet radiation belongs to. After description of the origins of ultraviolet radiation—the sun as the natural source and some artificial sources—main attention will be set on photochemical and photobiological effects. The energy of ultraviolet radiation can be absorbed by molecules (chromophores) and induce primarily or secondarily chemical alterations in biomolecules, from which the DNA is the most important target. The consequences of these alterations can lead to medically relevant acute, chronic or late effects in the mostly affected organs skin, eyes, or immune system. Beside the well-being effect of exposure to solar radiation the induction of vitamin D3 synthesis is one of the positive effects of ultraviolet on human health. After discussion of protection measures the article will close with some references to international efforts on UV management.