The United Nations Economic Commission for Europe (UN/ECE) International Co-operative Programme on Effects on Materials, including Historic and Cultural Monuments, has an extensive programme on material exposure in well defined environment. This report includes the environmental data from the third exposure year of temperature, relative humidity, time of wetness, sunshine hours, SO2, NO2 and O3 concentrations and precipitation amount and quality. A statistical treatment of the data has been carried out. 7 refs., 13 figs., 11 tabs