雾天气向霾天气转化时气溶胶颗粒物的动力学特性

Dynamical characteristics of aerosol particles from fog to haze weather

针对自然界中雾天气向霾天气转化的现象,提出建立和发展雾环境气溶胶颗粒物多效应的动力学模型。基于离散系统的颗粒群平衡方程和多重Monte Carlo算法,分别对雾形成阶段(凝并、冷凝和成核3个动力学事件占主导),雾发展阶段(凝并、破碎、沉积和成核4个动力学事件占主导)和雾消散阶段(破碎、蒸发和沉积3个动力学事件占主导)气溶胶颗粒物平均体积、颗粒数目随时间的演变过程进行研究。结果表明:气溶胶颗粒物的初始体积尺度为1,经过雾的生命周期进入消散阶段时,尺度为0.0156的细小气溶胶颗粒数迅速增加,1000 s时间已发展至初始值的8.12倍。研究结果解释了自然界中雾天气向霾天气转化的过程和物理机制。

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.