Simultaneous stratospheric volume mixing ratios (VMRs) measured inside and outside the Antarctic vortex by the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument in November 1994 reveal previously unobserved features in the distributions of total reactive nitrogen (NOy) and total hydrogen (H2O+2CH4). Maximum removal of NOy due to sedimentation of polar stratospheric clouds (PSCs) inside the vortex occurred at a potential temperature (&THgr;) of 500--525 K (~20 km), where values were 5 times smaller than measurements outside. Maximum loss of H2O+2CH4 due to PSCs occurred in the vortex at 425--450 K, ~3 km lower than the peak NOy loss. At that level, H2O+2CH4 VMRs inside the vortex were ~70% of corresponding values outside. The Antarctic and April 1993 Arctic measurements by ATMOS show no significant differences in H2O+2CH4 VMRs outside the vortices in the two hemispheres. Elevated NOy VMRs were measured inside the vortex near 700 K. Recent model calculations indicate that this feature results from downward transport of elevated NOy produced in the thermosphere and mesosphere. ¿ American Geophysical Union 1996