1334 A simple method to determine the cumulative dose in outdoor workers exposed to solar radiation

Abstract

Introduction Solar radiation may have adverse effects, both acute and long-term, on skin and eye, mainly due to the UV component. Outdoor workers are significantly exposed to solar UV radiation, but exposure is highly variable, depending on environmental, occupational and personal features. Outdoor workers’ exposure to Solar Radiation (SR) is still an underestimated risk factor in several countries, particularly in Italy, even if it has been included for years in the carcinogenic for humans by (IARC). The scarce attention paid by employers to this risk imports as an insufficient prevention, as well as a difficulty in recognising in retrospect the causal relation between the long time exposure of workers and the eventual skin cancer; in particular, this can happen when the melanoma occurs in body districts which were less exposed to direct SR. Individual exposure may be measured by using personal dosimeters, but presently operative concerns may limit or even prevent their usage in a lot of cases. Several indirect methods to assess UV exposure of outdoor workers have been proposed, with no general agreement. Also, there may be need to assess lifetime cumulative exposure of an individual worker for both epidemiological and legal purposes. This work describes a method for reconstructing the annual exposure dose starting from the data obtained by a questionnaire filled by the worker. Methods An algorithm has been developed for reconstructing the annual exposure dose of SR related to the worker. The mean radiant exposure of one month in a selected place was derived from satellite data (TEMIS-ESA) and the mean global irradiance on the same period was provided by ENEA on the basis of measured data; both data consider the cloudy coverage and the ozone column, and the satellite data are the mean of five years. The ratio of these two values gives a coefficient for estimating the mean erythemal dose of one month on the horizontal plane; successive corrections relative to the number of working hours and day, clothing, albedo and position of the body district exposed were applied. Results First validation tests demonstrated that the algorithm estimates the mean daily erythemal dose with an optimal approximation respect to the values deriving from on field measurement campaign. Successive validation test will be carried out with extensive measurements involving workers of specific sectors (fishing, farming, quarry). Conclusion The developed algorithm is an instrument useful for determining the cumulative UV erythemal dose of workers with the best possible level of approximation, since it was obtained on the basis of the previous working exposure derived from a questionnaire filled by the worker itself. The algorithm can be also used as prevention instrument for the previous evaluation of the occupational risk.