Ultraviolet exposure patterns

Abstract

Using new measurements of ultraviolet radiation, exposure by time of day and month of year are examined at nine urban locations in the continental United States. About 60% of the total annual ultraviolet radiation count is received between the 4 hour period, 10:00 am to 2:00 pm. Most people can substantially reduce their annual exposure levels by sheltering themselves during the noon-time hours of 11:00 am through 1:00 pm. Individuals who need to limit their sunlight exposure time, i.e., those of light skin pigmentation, should benefit most from the results of this study.