A recent determination by D. R. Bates of the Rayleigh scattering cross section (σRS) for air from 0.2 to 1 μm leads to a simple empirical formula (λ in μm) σRS = 4.02 × 10-28 λ4+xcm2 where x = 0.389λ + 0.09426 λ - 0.3228 for the spectral region 0.2 μm < λ < 0.55 μm ; the accuracy is within ±0.5%. From the visible at 0.55 μm to the infrared (i.r.) at 1 μm, the same accuracy can be obtained using a constant value, x = 0.04. The formula accounts for the degree of depolarization which varies with the wavelength according to the latest determination by Bates.