Synthesis of vitamin D and erythemal irradiance obtained with a multiband filter radiometer and annual variation analysis in Río Gallegos, Argentina

P. F. ORTE, E. A. WOLFRAM, J. SALVADOR, R. DELIA, N. PAES LEME, E. J. QUEL.

Lima

Congreso; RIAO-OPTILAS 2010 VII Reunión Iberoamericana de Óptica; 2010

In this paper we examined the annual variability of the erythemal solar radiation(a health risk) and the solar irradiance for synthesis of vitamin D (a health benefit) in RíoGallegos, Argentina. We use ultraviolet radiation measurements made by a multiband filterradiometer GUV-541 and a Brewer spectrophotometer located at CEILAP-RG Station(CITEFA-CONICET) (51 º 33' S, 69 º 19' W). These measurements are weighted withaction spectra published by the CIE (International Commission on Illumination). An action spectrum describes the relative effectiveness of different wavelengths in the generation ofa particular biological response. The analyzed data correspond to September 2008 -December 2009 period.The methodology usedto obtain the erythemal irradiance and synthesis of vitamin Dvalues combines irradiance measurements of a multiband filter radiometer with modeledvalues (output of radiative transfer model) and measurements of a Brewerspectrophotometer. This procedure increases the instrumental capabilities of thisinstrument.The synthesis of vitamin D and erythema are affected by UVB solar radiation. Therefore,its effect is strongly dependent of the stratospheric ozone amount, which undergoes largevariations in the Río Gallegos city due to ozone hole passage and its influence on thesesub-polar latitudes. We observed that could exist cases of sunburn for reasonable exposure in abnormalsituations of low total ozone column, resulting in high levels of ultravioletradiation. Furthermore, the synthesis of vitamin D through exposure to ultraviolet radiationwould be lower than the appropriate values to the majority of the year for theselatitudes. Therefore it is important to evaluate the annual variation of these quantitiesrealizing seasonal balance between this health risk and this health benefit.