The project aims at producing an ENVISAT-1 mission-long monitoring of the inorganic chlorine (Cly) and fluorine (Fy) loading in the Earth’s middle atmosphere, based on FTIR vertical column abundance measurements of the key related species HCl, ClONO2, HF and COF2 at 10 ground-based NDSC sites distributed worldwide. These Cly and Fy inventories will be completed with ClO and OClO measurements expected as Level-2 products from ENVISAT-1. The column abundances of the source gases CFC-12 and HCFC-22 will be used to place the stratospheric Cly and Fy evolution in perspective with the more complete sets of organic chlorinated and fluorinated compounds measured at the ground by the in situ networks NOAA-CMDL and AGAGE. The assimilation of the retrieved geophysical data bases will be performed through 3-D model calculations incorporating physical, chemical and transport characteristics of the global atmosphere.