Jcf. Wong et al., ANNUAL REDUCTION OF SOLAR UV EXPOSURE TO THE FACIAL AREA OF OUTDOOR WORKERS IN SOUTHEAST QUEENSLAND BY WEARING A HAT, Photodermatology, photoimmunology & photomedicine, 12(3), 1996, pp. 131-135
The total annual exposure to erythemally effective UVR was estimated f
or average work situations in a high exposure environment, viz, farm w
orkers in Southeast Queensland (27.5 degrees S), and the effect of hat
usage was examined. If no sun protection is used, the annual erythema
exposures for this group of workers at three facial sites: forehead,
nose and cheek are 40, 57 and 34 J . cm(-2) respectively. If a hat is
worn throughout the year, the exposures are reduced to 6, 19 and 20 J
. cm(-2), respectively. The mean ratio of exposure without the hat to
that with the hat (mean protection factor, MPF) was found to be 6 for
the forehead, 3 for the nose and 2 for the cheek. The risk of non-mela
noma skin cancers without the protection of the hat is estimated to in
crease by up to 100 times for basal cell carcinomas and 13 times for s
quamous cell carcinomas for a whole year of exposure.