Understanding the UVA environment at a sub-tropical site and its consequent impact on human UVA exposure.

Daily UVA and erythemal irradiance data on a horizontal plane at a sub-tropical site were measured during a period from March 2000 to February 2001. On a relative basis, UVA radiation was shown to be a greater concern to human exposure during the winter months than summer months. In summer (December to February), the peak daily UVA exposure was 205 J cm(-2) and in winter (June to August), the minimum daily value was 19 J cm(-2). The peak daily UVery exposure was 37 MED in summer and the winter minimum was 4 MED. The occupational work day UVA exposure to the vertex of the head was estimated using the collected UV data. The outdoor workers received 89% of the available UVA radiation whilst the home workers received 18% of the available ambient UVA radiation. This result parallels the exposure patterns of these two population groups, with the outdoor workers spending most of the working week outdoors, whilst the home workers spend small, intermittent time periods outdoors in the sun.