During late 1985, the Research Management Committee (RMC) of the National Crop Loss Assessment Network (NCLAN) decided the most ap propriate way to bring the NCLAN program to a successful conclusion was to hold an international conference. It was envisaged as an opportunity to present an overview of results from the NCLAN program and as a chance to view the results in the context of ongoing research by members of the international community. * Although we wanted the Conference to have an assessment orientation, it was also intended for the Conference to focus on current state-of-knowledge. The Conference was designed to overview the needs of crop loss assessment, current approaches to assessment, progress in the development of predictive models, the use of the information for economic predictions, and the application of the data in policy decisions. Every effort was made to assure a broad representation of ideas. The Conference program was developed to evaluate major issues that address regional/national assessments of impacts of atmospheric pollutants on agricultural production. Sessions were structured to address specific issues by invited speakers, and by contributed papers and posters. First, background needs for doing loss assessment research including specific approaches and a rather detailed review of the NCLAN program were addressed (Session I). Session II addressed the needs for defining the exposure environment (e. g. extrapolating to regional concentrations and exposure characterization). Field approaches for determining crop loss were reviewed in Session III."