The use of the Empirical Retrieval of Atmospheric air mass factor (ERA) technique for measuring water vapor content from Global Ozone Monitoring Experiment (GOME) is discussed. The ERA technique is designed to remove the problem of modeling the air mass factor by considering the oxygen slant concentrations as a good approximation to it. The atmospheric air mass factor is weakly dependent on the wavelength for the selected species and wavelength ranges. The molecular absorption cross section values are assumed to be constant at all atmospheric temperatures and pressures. The GOME aims to measure the global distribution of ozone and other trace gases through spectral analysis of the sunlight scattered from the Earth's atmosphere.