Tables of ambient solar ultraviolet radiation for use in epidemiological studies of malignant melanoma and other diseases

Abstract

There is little disagreement that exposure to solar radiation is a major factor in the aetiology of malignant melanoma and other skin tumours in white-skinned populations [1,2]. What is less clear is the type of sun exposure that is most important and the wavelengths in sunlight which are largely responsible, although it is believed that the ultraviolet component of sunlight is most relevant. Epidemiological studies provide the best direct evidence for the causation of skin cancer by solar radiation, especially for melanoma where there is no clearly relevant animal model, but cannot readily differentiate between different wavelength ranges. Both UVA (315–400nm) and UVB (280–315nm) radiation show carcinogenic actions in animals, and other skin changes and immunological effects in humans, and both have been classified as ‘probably carcinogenic to humans’ [2]. (So too has UVC (100–280nm) radiation but this is not relevant here as UVC does not reach the Earth’s surface). For melanoma there is strong evidence that intermittent and regular exposures have different effects [3], and for other skin cancers recent studies suggest that traditional dose models may be inadequate [4]. In order to explore dose-response relationships epidemiologists need access to data concerning the ambient levels of ultraviolet at various times throughout the day and for different times of the year and latitude. This paper presents these data in tabular form.