Comparisons of spore dosimetry and spectral photometry of solar-UV radiation at four sites in Japan and Europe

In order to develop monitoring and assessment systems of biologically effec tive doses of solar-UV radiation, concurrent measurements of spectral photo metry and spore dosimetry were conducted in summer months at four sites in Japan and Europe. Effectiveness spectra were derived by multiplying spectra l irradiance in 0.5 nm steps between 290 and 400 nm with the inactivation e fficiency of the spores determined using monochromatic radiation of fine wa velength resolution. Shapes of the effectiveness spectra were very similar at the four sites exhibiting major peaks at 303.5, 305.0, 307.5 and 311.0 n m, The dose rates for spore inactivation from direct survival measurements and from calculations by the integration of the effectiveness spectra were compared for 174 data points. The ratios (observed/calculated) of the two v alues were concordant with a mean of 1.26 (+/-0.24 standard deviation [SD]) . The possible causes for the variations and slightly larger observed value s are discussed.