|MadSci Network: Physics|
Several factors affect the penetration of ultraviolet radiation (UVR) into water. Pure water attenuates very little UVR and therefore it will very easily penetrate the typical water volume of a pool. However, 10-25 % of UVR is reflected (scattered) off the surface of the pool and never enters the water volume. Impurities in the water will have different attenuation characteristics than pure water but would probably be negligible in a typical swimming pool. I think that the bottom of the pool will absorb most of the UVR; of course this will depend upon the scattering characteristics of the material. When a formula is considered the impurities in a water volume must be considered and thus complicates the process. Much research on the penetration of UVR into water bodies has been performed to study the effects on biological systems. I would suggest a search into this area of research for a comprehensive treatment of this topic. [note added by MadSci Admin: Check this reference for the absorption characteristics of water: http://www.lsbu.ac.uk/water/vibrat.html]
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