The European Commission, DG XII, has published a report entitled "Effects of air pollution on agricultural crops in Europe". The report presents the proceedings of a symposium on "Air pollution and crop responses in Europe" which was organized by the Commission on 23-25 November 1992 in Belgium. The symposium was a conclusion of the European Open-Top Chambers project concerning crop responses towards air pollution. The project was launched by DG XII in 1985 under the First Framework Programme for research and technological development and demonstration. The objective of the project was to find out whether ambient concentrations of atmospheric pollutants have an influence on crop growth in rural areas. This hypothesis was tested by several countries by means of open-top chambers installed at sites remote from industrial and major urban areas. The report contains a general synthesis of the results obtained by the different teams during the project and of the actual knowledge of effects of air pollutants on crops.