We present both experimental measurements and Monte-Carlo-based simulations of transmission polarization to analyze the concentration variation effects of the water fog particles. Simulations based on Monte Carlo program have been conducted for tracking photon transmission process with the radius and refractive index of water fog samples under different optical thicknesses. Correspondingly, experiments with an environment modulation system show that by controlling the water fog concentration, the Mueller matrix and the depolarization characteristic change in a regular way. Both the simulation and the experimental results show a good distinction of Mueller matrix among the light, moderate, and thick fog samples, and the depolarization property of thick fog environment is more prominent. Moreover, circular polarization persists better than linear polarization in more serious fog. These works can provide a tool to examine different media concentrations by the polarization patterns and broaden the application range of polarization.