Biological effectiveness of solar UV radiation in humans.

Solar UVB radiation is prejudicial to the health of humans in a number of ways. Erythema and photodermatoses are acute reactions of the skin; keratitis and conjunctivitis are acute reactions of the eye. Various types of skin cancer, accelerated aging of the skin, and cataract formation in the crystalline lens are reactions that appear with great latency. UV radiation can also cause damage to the immune system and DNA. For the period 1981-1991, an increase in erythemal effective UVB radiation of +(7 +/- 4)% per decade was measured in a non-polluted high mountain area (Jungfraujoch, 3576 m a.s.l., Switzerland). This increase is related to a decrease in stratospheric ozone. The effects on human health are discussed. A 10% ozone reduction increases non-melanoma skin cancer by 26% and cataract by 6 to 8%.