EFFECT OF STRATOSPHERIC OZONE DEPLETION ON TERRESTRIAL ULTRAVIOLET-RADIATION - A REVIEW AND ANALYSIS IN RELATION TO POLYMER PHOTODEGRADATION

Current satellite and ground-based data indicate a long-term decrease in global ozone levels of 2.7 +/- 1.4% per decade, although recently the rate may have increased to about 4% per decade outside of the tropics. There is yet little evidence of an accompanying wide-spread increase in terrestrial UV levers, but calculations predict increases of a similar magnitude in coming years. The manifestation of increased UV will be as a broad band centered about 310 nm with only very little absolute increase in wavelengths shorter than 295 nm. Unless sustained ozone losses exceed 15% during the summer months, the effect should be inconsequential for most polymers. The effects of sun position on daily and seasonal variations in UVB are discussed.