Ozone depletion, related UVB changes and increased skin cancer incidence

摘要: Stratospheric ozone at middle latitudes shows a seasonal variation of about ±20%, quasi-biennial oscillation 1–10% range and long-term in which the level was almost steady up to 1979 declined thereafter present day by 10%. These variations are expected be reflected solar UVB observed ground, but an opposite direction. Thus should have had increase 10–20%, cause skin cancer incidence 20–40%. Skin has increased all over world, e.g. 90% USA during 1974–1990. It is popularly believed that this related recent depletion. This seems incorrect, for two reasons. Firstly, too large (90%) compared with value (40%) from Secondly, does not develop immediately after exposure UVB. The sunburns may occur within hours; development detection take years, even decades. Hence since 1974 (no data available earlier periods) must occurred due 1950s 1960s, when there no Thus, attributed harmful levels existing accentuated later depletion (which started only much later, 1979) other causes, such as longer human life span, better screening, increasing tendencies sunbathing beaches, etc., affluent societies. On hand, associated increases will certainly their toll; effects noticed now years or decades now. concern future expressed Montreal Protocol reducing controlling CFC production justified, especially because animal plant also. However, so far (entirely) depletion, causes need investigated urgently and, if possible, remedied. Otherwise, deaths continue controlled recovered. There room complacency. If nothing else use protective screens creams avoiding sunlight peak hours (10:00–15:00 h) strongly recommended. © 1998 John Wiley & Sons, Ltd.