The operation of EMEP at the international level was designed to be carried out in two parts: one dealing with the chemical activities (monitoring) and the other with the meteorological activities (modelling). The co-ordination and intercalibration of chemical air quality and precipitation measurements are carried out at the Chemical Coordinating Centre (CCC) at the Norwegian Institute for Air Research (NILU). The CCC heavily relies on the active participation of the Parties that are running the monitoring sites. Two Meteorological Synthesizing Centres in different parts of Europe, one Western centre (MSC-West) at the Norwegian Meteorological Institute and one Eastern centre (MSC-East) at the Hydrometeorological Service in Moscow, are responsible for the final evaluation of the meteorological data, both working in close cooperation with CCC. MSC-West is responsible for the modelling assessment of sulphur, nitrogen photooxidant pollutants and atmospheric particles. The modelling development for heavy metals and POPs is the responsibility of MSC-East.
The Centre on Emission Inventories and Projections (CEIP), which is hosted at the Environment Agency Austria (Umweltbundesamt), collects emissions and projections of acidifying air pollutants, heavy metals, particulate matter and photochemical oxidants from Parties to the Convention; reviews submitted inventories in order to improve the quality of reported data; and prepares data sets as input for long-range transport models.