Infrared (IR) in situ radiance observations, 8.0-14.0 μm (714-1250 cm-1) and 9.5-11.5 μm (870-1052 cm-1), of the West African Harmattan haze during the 1974 Global Atmospheric Research Project Atlantic Tropical Experiment field phase made possible the determination of some of the radiative properties of this tropospheric phenomenon. This in turn permitted development of a simple calculation model for radiative transfer throught the haze. Radiometric observations of the dust haze, reaching from 600 m to 6.25 km, were analyzed for haze IR transmission. A transfer model incorporating these transmission properties gave an average calculated IR cooling rate of 0.09¿C h-1 for the entire haze layer compared to a haze-free cloudless troposphere cooling rate of 0.06¿C h-1 for the same levels. The haze volume absorption coefficient was approximately 0.042 km-1 for layers of all depths. This uniformity of the haze transmission was further evident in the direct correlation of its transmission and optical depth.