Study on the ocular biological effective ultraviolet irradiance and its risk evaluation in different altitude area

Objective To study on the ocular biological effective ultraviolet irradiance and its risk evaluation in two different altitude areas. Methods A self designed rotating manikin and dual-detector spectrometer were used to monitor the intensity of ocular exposure to UV irradiation under clear skies in Xichang and Shaoxing, of which the intensity of every time point, the average intensity of every hour, the accumulative total dose of every hour and the monitored accumulative total dose in whole day were calculated respectively. Results The diurnal variations of ocular biological effective ultraviolet irradiance and ratio of that to safety limit all exhibited bimodal distribution in Xichang and Shaoxing, the maximum ratio were 23.6 and 13.44, respectively. The accumulative total dose of every hour also exhibited bimodal distribution in two areas, the maximum of Xichang were 80.3 J/m2 and 69.87 J/m2, the ranges of solar elevation angle were 44.4°~55.4° and 54.3°~65.2°; the maximum of Shaoxing were 43.13 J/m2 and 46.75 J/m2, the ranges of solar elevation angle were38.9°~47.2° and 50.7°~60.2°. The monitored accumulative total dose in whole day in Xichang and Shaoxing were 564.7 J/m2 and 396.5 J/m2, respectively. Conclusions The diurnal variations of ocu-lar biological effective ultraviolet irradiance, ratios of that to safety limit and the accumulative total dose of every hour all exhibit bimodal distribution in two different altitude area. Under the same solar elevation angle, all data of Xichang show significant higher than those of Shaoxing. Key words: Altitude; Eye; Biological effective ultraviolet irradiance; Risk evaluation