This report summarizes the work of the RIVM Coordination Center for Effects (CCE) and National Focal Centers (NFCs) for Mapping over the past two years. The report includes European maps of critical loads of acidity and sulphur, produced for the United Nations Economic Commission for Europe's (UN ECE) Convention on Long-range Transboundary Air Pollution (LRTAP). The primary task of the critical loads mapping program during this period was to compute and map critical loads of sulphur in Europe. Since the first European maps of critical loads were published in 1991 (Hettelingh et al.), a number of revisions and improvements have been made with respect to data and methodologies. Efforts were also undertaken to enhance the scientific foundations and policy relevance of the critical load program, and to foster consensus among producers and users of this information. Three mapping workshops organized by the CCE during 1992-1993 (Bilthoven, January 1992; Katowice, September, 1992; and Madrid, March, 1993), as well as a wordkshop on critical loads of nitrogen (Lökeberg, April 1992) provided forums to review work conducted to date, and to discuss methods and other issues concerning future work. The report describes the calculation methods used, and resulting critical loads maps, based upon the outcomes of these workshops. It provides the reader with a comprehensive overview of the current status of the work related to critical loads in Europe.
