Human exposure to solar ultraviolet radiation.

Solar ultraviolet (UV) irradiation depends upon the local UV climate, people's behaviour. Behaviour includes the time spent outdoors and the use of photoprotective agents. In adult life, a British indoor worker in the UK might typically receive 30% of his or her annual UV exposure from sun-seeking holidays, 40% from summer weekends, 20% from casual weekday exposure between April and September and just 10% from sun exposure during the 6 month period October to March. Whilst climatic factors do influence levels of UV radiation (UVR) at the Earth's surface, it is people's behaviour out of doors that has a much greater impact on personal solar UV irradiation. Methods of personal protection include: avoiding direct sunlight in summer around noon; seeking the shade; wearing clothing absorbs UVR; wearing hats that shade face and neck; and using topical sunscreens.