Equivalent cross section polydisperse and non-spherical particles found as the ratio of the mean square cross-section of the middle cross section. To do this, get a digital image of dust particles through a microscope. Particles corresponds to the cross-section 1.4 10-8 m2 (29%). Equivalent cross section can be compared monodisperse. Then analyzed the scattering layer of non-spherical particles can be replaced by a layer of monodisperse with this cross section. In probing the surface layer of the atmosphere contribute to the equivalent cross-section of a molecular component is much smaller than the cross section on the dust particles. The proposed method can be used for remote sensing measurement assurance microstructure scattering media.