Number 192 (Story #3), August 30, 1994 by Phillip F. Schewe and Ben Stein THE EXPERIMENTAL ULTRAVIOLET INDEX , to be issued daily by the National Weather Service, is a forecast of the noontime ultraviolet level in 58 U.S. cities. So in addition to smog, pollen, and the weather itself, people can now worry in a quantitative way about the cancer- causing or cataract-causing effects of UV. An index of 6, for example, is considered "moderate." At that level a person with skin very susceptible to sunburn, would burn after 10 minutes of direct exposure, while a much less susceptible person would burn after 50 minutes. The general advice of the Environmental Protection Agency is that if you can see your shadow, you may want to use some protection against UV radiation. (Science News, 23 July.)