Since discovery of the "ozone hole", monitoring of longterm trends and geographical variability of UV irradiance and howit impacts our environment has became increasingly important. Acontinuing difficulty in judging these impacts is the lack ofcoordinated, world-wide W monitoring networks that produceresults that can be compared at the level of precision andaccuracy needed to detect trends in irradiance that may be or arelikely to be occurring.In Phase I we demonstrated that the GUV-511 radiometers arestable and able to determine the biologically-weighted UVirradiances of interest to the scientific community, and thatthey can be integrated into coordinated, automated networks. Wehave evidence that they can detect changes in ozone and cloudcover, crucial features in distinguishing varying changes in UV.In Phase II we will develop tools that wit allow these networksto continue to be operated in a coordinated manner with a fullset of quality control measures including field calibrationmethodologies linked to national laboratories that will enablethese networks to detect global trends in W irradiance and thatwill at ow results to be intercompared with other networks, bothnational and international.Potential commercial applications of the research:The fact thatozone depletion is occurring is widely known by the generalpublic. Several federal agencies are involved in programs rearedto understanding its impact. Most countries in mid- orhigh-latitudes are establishing or desire to establish monitoringnetworks. Unfortunately, no cost-effective instrumentation hasbeen widely acknowledged to be adequate for the task. We proposeto deliver a proven, cost-effective, internationally-based methodfor gauging the impact of changes in the ozone layer that meetsmany of the objections raised against using instruments costing less than $50,000.