Summary and evaluation; conclusions and recommendations also in French and Spanish.

First edition published in 1979.

A state-of-the-art review of the many lines of evidence - whether at the molecular or the clinical level - linking exposure to ultraviolet (UV) radiation to a range of adverse effects on human health. The report, which responds to concern over the depletion of stratospheric ozone and a corresponding increase in levels of UV radiation, makes a special effort to distinguish between established biological effects and those that have been reported as preliminary or isolated results, or as hypotheses proposed to explain observed results. By distinguishing areas of consensus from areas of continuing controversy, the book aims to establish a solid, scientific foundation for identifying precise health hazards, designing targeted programmes for prevention, and making realistic predictions for the future. Since UV radiation is an established human carcinogen, the report concentrates on the mechanisms by which UV radiation exerts its toxic effects and on the many environmental, constitutional, ethnic, behavioural, and other factors that influence individual risk. The opening chapters describe the physical characteristics of the electromagnetic spectrum and discuss the properties of different sources of UV radiation, including the sun, incandescent sources, gas discharges, electric discharges, fluorescent lamps, lasers, and sunbeds. The second chapter discusses human exposures occurring in various occupations, in medicine and dentistry, and in sunbathing, outdoor recreation, and other elective behaviours. Dosimetric concepts are reviewed in the third chapter, which concentrates on principles important to the design and interpretation of studies. Studies of the cellular and molecular effects of UV radiation on biological systems are reviewed in the next chapter, which notes that DNA is the most critical target for damage caused by UVB and UVC radiation. A review of findings from animal studies of both acute and chronic exposures concentrates on evidence of skin carcinogenesis, altered immune responses, including modification of susceptibility to infectious diseases, and damage to the eye. Evidence also supports the conclusion that many different genes and several viruses, including HIV, are activated by UV radiation. The most extensive part of the book reviews the large body of evidence from human studies of effects on the skin, immune function, and the eye. Apart from evidence that sun exposure causes cutaneous melanoma and non-melano-cytic skin cancer, these chapters cite evidence that exposure to UV radiation can enhance the risk of infectious diseases, reduce the effectiveness of vaccines, accelerate the development of AIDS in seropositive individuals, and cause a number of acute and chronic adverse effects on the eye. The remaining chapters summarize some well-documented effects on plant and aquatic ecosytems caused by UV radiation, assess health hazards and preventive measures for each of the main categories of exposure, and set out recommended international guidelines for establishing exposure limits.

DC.HQ

eng rus.

per pol.

WHODOC

WHO monograph

4