Abstract:
The city of Pretoria in South Africa receives considerable solar ultraviolet radiation (UVR) because of its
low latitude (22–35°S) and relatively clear skies. Certain meteorological factors affect the amount of solar
UVR that reaches the ground; the most dominant factors being stratospheric ozone, cloud cover and solar
zenith angle. It is known that overexposure to solar UVR may lead to the development of adverse health
conditions, the most significant being skin cancer. Outdoor workers spend a significant amount of time
outside and are thus susceptible to this risk. In this case study, we estimated, for the first time, the realtime
solar UVR exposure of an outdoor worker in Pretoria. Measurements were made on 27 and 28 May
2013 using a handheld ultraviolet index (UVI) meter calibrated against a science-grade biometer at the
South African Weather Service in Pretoria. Personal exposure estimation was used to discern the pattern in
diurnal and annual sunburn risk for the outdoor worker. Ambient UVR levels ranged from 0 UVI to 4.66 UVI
and the outdoor worker’s potential exposure estimates regularly exceeded 80% of these levels depending
on the time of day. The risk of sunburn was evident; however, actual incidents would depend on individual
skin photosensitivity and melanin content, as well as sun protection used. Further research is needed to
determine the personal exposure estimations of outdoor workers in other provinces in which solar UVR levels
may be equally high, or higher than those in Pretoria.
