Abstract <p>Most measurements of aerosol attenuation of the atmosphere are carried out in the visible and near-infrared regions of the spectrum. However, many atmospheric optics tasks require data on the spectral behavior of aerosol extinction coefficients in the visible and IR regions, including the atmospheric “transparency window” 8–12 μm. In this regard, models that make it possible to calculate attenuation in the IR region based on measurements in the visible region are of great interest. A one-parameter model of the spectral behavior of the aerosol extinction coefficient for the surface air layer is suggested. The input parameter of the model is the aerosol extinction coefficient at a wavelength of 0.55 μm or the meteorological visibility range <i>S</i>_m. The model enables one to calculate the mean aerosol extinction coefficient in the wavelength range 0.44–12 μm at meteorological visibility range <i>S</i>_m &gt; 8 km. The model can be used to evaluate the efficiency of different optical systems and to separate aerosol attenuation into submicron and coarse components.</p>