Comparisons of biologically effective doses of solar UV-radiation determined with spore dosimetry and spectral photometry in 2000-2003 at Southern Space Observatory, Brazil

In order to assess the impact of solar-UV radiation on biosphere and human health, spore dosimetry and spectral photometry have been performed in parallel at the Southern Space Observatory, São Martinho da Serra in the State of Rio Grande do Sul (southern region of Brazil, latitude 29.44°S, longitude 53.8°W). Daily and monthly cumulative doses obtained from spore dosimeters were compared with the doses derived from the integration of the daily effectiveness spectra obtained by multiplications of the spectral irradiance from Brewer spectrophotometers with the action spectra for spore inactivation and erythema induction. For daily exposures performed on 24 days in 2002-2003, the values of the observed spore inactivation doses (SID) and the calculated ones were closely correlated with a mean ratio (observed SID/calculated SID) of 0.7 ± 0.3, while the values of the observed SID were regressed to the erythemal doses (MED) by a power function with a correlation coefficient r2 ∼ 0.9. For cumulative monthly doses, the values of calculated SID and MED were regressed to the observed values of SID by power functions for each year with r2 = 0.5-0.9 and r2 = 0.5-0.9, respectively. The applicability of the spore dosimetry for continuous long-term monitoring of biologically effective doses of solar-UV radiation has been verified in this work.