Contact: Barbara McGehan FOR IMMEDIATE RELEASE
4/21/97`
A new study published in the April 20 issue of the Journal of Geophysical Research says that there is no clear evidence that UV radiation decreased in the 1980's as had been previously reported in a 1988 Science paper. Available measurements seem, instead, to support a slight increase in potentially harmful UV radiation over the mid-latitudes during the 1980's.
E.C. Weatherhead, a researcher in the National Oceanic and Atmospheric Administration's Air Resources Laboratory (ARL) in Boulder, Colo., and colleagues from the University of Wisconsin and University of Chicago, conducted a three-year study in which data measured at 14 ground stations were analyzed. The new analysis made use of available information on cloud cover, ozone and temperature as well as a variety of other atmospheric data. It shows that UV was increasing during the 1980's and is continuing to do so.
UV radiation has a major impact on the environment and on human health. It contributes to cataract formation, skin damage and cancer as well as suppression of the immune system. The previous study published in 1988, sponsored by the National Cancer Institute (NCI), reported a decline in UV radiation during the time period 1974- 1985.
Weatherheads's analysis disputes that conclusion. According to Weatherhead, "It is likely, based on ozone and cloud measurements, and on our present understanding of the instruments, that UV was increasing over the continental United States by a few percent in the 1980's and has continued to increase in the 1990's."
UV levels are supposed to reach their maximum in the next decade when ozone is expected to reach its minimum. The ozone layer shields the Earth from the harmful effects of UV radiation, but it has been thinning due to human activity, and it will continue to do so until sometime in the next century.
Under increased UV levels, higher costs are incurred in terms of human health, environmental stress and medical expenses. Sun avoidance is particularly important for children and those whose immune systems may already be stressed, such as AIDs patients. The few hours around noon contain almost half of the daytime dose of UV. The National Weather Service presently produces a UV index to educate the general public on expected levels of UV radiation.