The knowledge of both the size distribution and the composition (refractive index) of atmospheric particles is important for the understanding of the radiative balance of the Earth and the cloud life cycle. These parameters modify the phase function and the polarization characteristics of the scattered light. The laboratory nephelometer (designed by LaMP) makes possible to characterize the optical properties of a population of aerosols. It was performed sensitivity tests of dual-polarization polar nephelometer (D2PN) data to optical and microphysical parameters of population of spherical aerosol particles. Measurement errors were modeled as Gaussian random variables with zero mean and a standard deviation of 10%. It is shown that data of the D2PN enable to retrieve microphysical parameters along with the assessment of the refractive index