In 2000 it is proposed to operate an atmospheric programme consisting of a monitoring and a modelling part and composed of 3 programme modules. The monitoring programme consists of two parts. I. It is proposed to continue the weekly measurements of acidifying components and heavy metals at Station Nord in north-east Greenland for assessment of atmospheric levels and trends. The measuring programme includes also highly time resolved measurements of Ozone and of total gaseous Mercury (TGM). The results will also be used for continued development and verification of the transport model calculations. Receptor modelling of the pollution composition will be used for identification and quantification of the source types that influence the atmospheric pollution in north-east Greenland. Comparison of the two sets of modelling results is expected to give better models. II. The purpose of the project is the operation of a permanent air monitoring programme in the populated West Greenland at a location which is representative for transboundary air pollution. The most promising sites are located in the Disko Bay area and in the vicinity of Nuuk. The objectives are to obtain data on the concentration levels of air pollutants that can be used for assessing seasonal variations and trends and for studying long range transport of pollutants mainly from North America to West Greenland. The purpose is further to provide data for development and improvement of long range transport models that can be used to identify the origin of the pollution and its transport pathways. The results from measurements and model calculations will be used to assess the magnitude of deposition to sea and land in this populated region of Greenland. III. In the proposed modelling programme the operation, application and maintenance of the current basic hemispheric model will be continued. Results on origin, transport, and deposition of contaminants on land and sea surfaces in the Arctic are essential for interpretation and understanding the Arctic air pollution. The model will be developed to improve the spatial and temporal resolutions, as well as the accuracy by including physically and mathematically better descriptions of the key processes treated in the model. The work to expand the model to include also non-volatile heavy metals, such as Cadmium and Lead on an hemispheric scale will be continued. Since the atmospheric chemistry of Ozone and Mercury seem to be strongly connected in the Arctic it is planned to continue the development and testing of a model module for hemispheric transport and chemistry for ozone and mercury to assess the origin and fate of this highly toxic metal in the Arctic.