Biologically Weighted Dosimetry of Solar UV Radiation

Abstract

The main aim of the research project is to obtain base-line data on the biologically effective solar UV B irradiance and its diurnal and seasonal variation. Biological weighting of the spectral irradiance will be achieved by using a biofilm which consists of immobilized bacterial spores as a UV-sensitive target. The first objective is to ensure the reliability of the biofilm as a biological dosimeter, in- dicative for DNA damaging efficiency of solar UV-light. For this pur-pose a calibration procedure will be established that determines the responitivity of the biofilm. The second objective will be to prove the reliability of the biofilm as field dosimeter to measure the bio-logically effective solar UV irradiance. For this purpose, in two field campaigns at IFU, a direct dosimetric comparison will be per- formed of the biologically effective dose of sunlight, determined by two different and independent methods; the biofilm on the one hand and physical measurements of spectral irradiance with application of biological weighting functions, on the other hand. The third ob- jective will be to initiate a continuous biological dosimetry of solar UV irradiance. For these measurements two sites of different levels of pollution have been selected, (1) a site in the Alps at IFU where the biofilm dosimetry will be performed in combination with spectroradiometry and (2) an urban site at DLR. On each site, the dosimetry data will be complemented by meteorological data.