Absorption and emission spectra obtained at the Observatoire du Pic du Midi in the French Pyrenees permit to deduce the nitric acid integrated column and lead to a value of 1. 2 x 10**1**0 mol. /cm**3 at the altitude of 22 km. CFCl//3 is found to be mixed in the troposphere with a value of 148 ppt. No evidence of HNO//4, HNO//2 or NH//3 was observed. The difficulties in observing H//2O//2 and in obtaining accurate values for O//3 and CF//2Cl//2 are discussed.