UV-Biometer - The usage of erythemal weighted broadband meters for other biological effects.

In this paper, we pick up the idea of the "UV-Biometer": the use of erythemal weighted broadband meters for other photobiological endpoints. Therefore, nine different types of broadband meters were considered. A necessity for their calibration is the availability of an action spectrum for the respective effect over the complete solar ultraviolet (UV) radiation range. Unfortunately, such action spectra are rather rare. Here we used the action spectra for non-melanoma skin cancer, DNA-damage, clearing of psoriasis, ICNIRP's workers protection and persistent pigmentation. The action spectrum for vitamin D photosynthesis is taken to estimate the effect of missing effectiveness values in the UV-A range. Application shows that high uncertainties occur especially at low solar elevations. Calibration factors in dependence of total ozone and solar elevation were calculated for all broadband meters and all effects. Analysis shows, that not all of these effects are as appropriate as erythema. The calibration for all effects was applied for a broadband meter that measures the UV-Index operationally within the Austrian UV-Index network. As most of these action spectra have threshold limit values or minimum dose equivalents, irradiance was converted into threshold exposure times. Uncertainties from total ozone during routine operation are estimated. Additionally, we derived conversion factors for erythemally effective irradiance to these effective irradiances. This delivers an easy way to gain biologically effective irradiance without the need of knowing the properties of the instrument. However, this introduces additional uncertainties and not all conversions should be applied.