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The major source of ultraviolet (UV) radiation is the sun. The amount of solar radiation
reaching the Earth’s surface depends on latitude, time of day and year, and cloud cover.
UV radiation is increasing worldwide with the thinning of the protective ozone layer.
UV radiation causes malignant melanoma of the skin and other skin cancers. The risk depends
on skin color and type, and is higher if exposure occurs in childhood. The incidence of
melanoma is high in countries with pale-skinned populations of European origin and high
levels of solar radiation. The incidence of non-melanoma skin cancers is also very high
in these countries, and they are the most frequent type of cancer diagnosed, although very
rarely fatal.
Melanoma has shown striking increases in incidence in many white-skinned populations, probably
because of increasing recreational exposures to UV. In Europe, the melanoma incidence is
highest in the north, not the sunny south, probably because intermittent exposure of pale
skin is more important as a cause.
The value of sunscreen in protecting against melanoma is controversial. Sunscreens are only a part
of a sun-safe strategy, which includes wearing sunglasses, hats and protective clothing, staying
out of the sun at midday, and providing shade structures for outdoor venues.
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