Updated volume mixing ratio profiles of ClONO2, HCl, and HF are reported from a reanalysis and reinterpretation of solar infrared absorption spectra obtained with the Atmospheric Trace Molecule Spectroscopy instrument on board Spacelab 3 (April 29 to May 6, 1985). These analyses incorporate improved spectroscopic parameters as well as instrumental and observational corrections made to this series of infrared spectra. While the HCl and HF results and their precisions reflect changes essentially below 30 km from the use of smaller pressure-broadened half-widths, the ClONO2 profiles have changed significantly as a consequence of adopting improved sets of line parameters which include a more realistic temperature dependency appropriate for stratospheric studies. The new ClONO2 results have an overall accuracy of ¿20%; when expressed in terms of vertical column abundances above their altitude span, they are in satisfactory agreement with values derived from airborne and ground based investigations. ¿ American Geophysical Union 1990