Patterns in the received facial UV exposure of school children measured at a subtropical latitude

Abstract

Polysulfone (PS) dosimeters have been employed to measure the erythemally effective UV exposure to the vertex, nose, cheek, chin and side facial sites of 45 volunteer high school students from Hervey Bay, Australia (25.3 degrees S 152.9 degrees E). The results of a series of 1 h outdoor sport trials (basketball and soccer) found the mean student facial exposure, determined as the arithmetic average of facial site exposures of unprotected students (no hat) to protected students (hat), varied from 140 +/- 82 J m(-2) (1sigma) to 99 +/- 33 J m(-2) (1sigma), respectively. All hourly student facial exposures recorded over the study period were found to exceed the National Health and Medical Research Council's adopted safe daily limit of 30 J m(-2). Facial exposure relative to the received ambient UV increased to the nose at higher (winter) solar zenith angles (SZAs) compared with lower (summer) SZA ranges for both protected and unprotected students. The protection offered by the broad-brimmed hats was reduced significantly to the lower chin facial site at the higher SZA range, indicating that the style of hat used offers best protection in summer to the upper facial regions at most risk of receiving a high exposure when no hat protection is used. Variations to specific student facial exposure sites were measured between both basketball and soccer players. Variation in student facial exposure was further examined with respect to cloud cover and comparisons to manikin headform measurements were also made. The study results indicate that hats alone are not adequate forms of sun protection in a school environment. Schools aiming to achieve acceptable safe limits of facial exposure may need to further consider the effectiveness of hat protection with increasing SZA, cloud cover and head position relative to the sun that is specific to the scheduled outdoor activity.