Ultraviolet Exposure: Health Effects

Abstract

Ultraviolet (UV) 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 produces positive effects on humans, but there are also adverse effects that should be considered. This article describes the physical background to establish a basis for understanding the nature of electromagnetic radiation to which UV radiation belongs. After description of the origins of UV radiation – the sun as the natural source and some artificial sources – attention will be set on photochemical and photobiological effects. The energy of UV radiation can be absorbed by molecules (chromophores) and induces primarily or secondarily chemical alterations in biomolecules, of which the DNA is the most important target. The consequences of these alterations can lead to medically relevant acute, chronic, or late effects in affected organs, including the skin, eyes, and immune system. Besides the well-being effect of exposure to solar radiation, induction of vitamin D 3 synthesis is one of the positive effects of UV on human health. After discussion of protection measures, this article will close with recent references to international efforts on UV management.