Diffuse solar ultraviolet radiation.
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Biomedical subjects
Publications and source records attributed to Alfio V Parisi.
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The variation of the biologically damaging solar UV (UVBE) enhanced by clouds above that of clear sky UVBE has been investigated. This was undertaken for summer through to winter for SZA of 5 to 60 degrees employing an integrated automatic cloud and spectral UV measurement system that recorded the solar UV spectra and the sky images at five minute intervals. The UVBE calculated with action spectra with higher relative effectiveness in the UVA produced the lower percentage of cloud enhanced cases. The DNA UVBE provided the highest percentage of cloud enhanced cases compared to the total number of UV scans with 2.2% cloud enhanced cases. As a comparison, the plant and fish melanoma UVBE provided the lowest percentage of cloud enhanced cases with 0.6 to 0.8% cloud enhanced cases. For the cases of cloud enhanced UVBE, the average ratio of the measured UVBE to calculated cloud free UVBE for the photokeratitis, cataracts, plant, generalized plant damage and fish melanoma action spectra was 1.21 to 1.25. In comparison, the highest value of 1.4 was for the DNA action spectrum.
Polysulphone dosimeters using a simple to use filter have been developed and tested to provide an extended dynamic measurement range of personal solar UV exposures over an extended period (3 to 6 days). At a Southern Hemisphere subtropical site (27.6 degrees S, 151.9 degrees E), the dynamic range of the filtered polysulphone allowed measurements of erythemal exposures to approximately 100 minimum erythemal dose (MED) for a change in optical absorbance at 330 nm (deltaA330) of 0.35. In comparison, unfiltered polysulphone dosimeters were exposed to approximately 8 MED for the same deltaA330. The error associated with the use of the filtered polysulphone dosimeters is of the order of +/-15%, compared with +/-10% of the unfiltered variety. The developed filtered polysulphone dosimeter system allowed the measurement of erythemal UV exposures over 3 to 6 days at a subtropical site without the need to replace the dosimeters because of saturation. The results show that longer-term measurement programs of personal solar UV have been made more feasible with the use of these polysulphone dosimeters with an extended dynamic range compared with unfiltered polysulphone dosimeters.
The methods presented in this paper allow for the estimation of human UVA exposure using measured UVA irradiance values. Using measured broadband UVA irradiances over the period of a year, it was estimated that for humans in an upright posture and not moving the head with respect to the body, the nose received 26.5% of the available ambient UVA radiation, whilst the shoulders and vertex of the head received 81% and 100% respectively of the available ambient UVA radiation. Measurement of the exposure ratios for a series of solar zenith angles between 90 degrees and 0 degrees will allow extension of this technique to other latitudes.