NILU is strongly engaged in the activities of the 4th International PolarYear. The institute is international coordinator of the core project POLARCAT and responsible for the atmospheric research and monitoring programme at the Troll Station in Antarctica (Atmo-TROLL). Furthermore, NILU contributes to the funded IPY projects COPOL and ICESTAR and the coordination activities Polar-AOD, ORACLE-O3 and IASOA. NILU is also the coordinator of the IPY educational project Global-POP.