Abstract: Multi-effective dynamics models of aerosol particles in the fog layer were established and developed to depict the natural phenomenon for conversion from fog to haze weather. Based on the population balance equation (PBE) of discrete system and the Multi-Monte Carlo (MMC) method, the evolution processes of average aerosol particle sizes and particle numbers with the time were simulated numerically for three stages of fog, which involve the formation of fog (dominated by aerosols dynamical effects of coagulation, condensation and nucleation), the development of fog (dominated by aerosols dynamical effects of coagulation, breakage, deposition and nucleation) and the dissipation of fog (dominated by aerosols dynamical effects of breakage, evaporation and deposition). The results indicated that the initial volume of aerosol particle is one. The numbers of particles with 0.0156 of volume-size are increased quickly when the life cycle of fog comes into the dissipation stage. At the time of 1000 s, the numbers of smaller-size particles are 8.12 times higher than those of initial time. The above results reveal the process and physical mechanism of fog conversion into haze weather in nature.

Key words: Fog-haze weather, Aerosol, Particle population balance modeling, Dynamics characteristic, Multi-Monte Carlo method, Fog-haze weather, Aerosol, Particle population balance simulation, Dynamical characteristic, Multi-Monte Carlo method