A combination of meteorological data and measurements of the CFCs is used to assess the chlorine activation in January 1992 during the EASOE campaign. Large activation can be expected when the coldest region occurs inside the polar vortex, as during early January. In mid January activation on the edge of the vortex, where the available chlorine is lower, should also have occurred. We consider the subsequent fate of this activated air, a small fraction of which clearly mixes into middle latitudes. A situation where extra-vortex air mixes into the vortex is also considered. ¿American Geophysical Union 1994