Analytical Solutions of the PM2.5 Diffusion Model and its Application

Air pollution has no national boundaries, which has caused widespread concern around the world. In order to analyse the diffusion and distribution characteristics of the particulate matter smaller than 2.5 micrometers (PM_2.5), the PM_2.5 diffusion model was established. By comparatively analysing the solutions of instantaneous point source equation with and without wind, the solution of continuous point source equation with wind, and the correction solution of an elevated point source model; the conclusion was drawn that the Gauss smoke cloud model adopted can solve the problem of diffusivity of (PM_2.5). The results show that the Gauss smoke model with wind can reliably analyse the actual problem by numerical simulation and the monitoring data in Xi'an of China. Through the analysis of the causes and general rules of PM_2.5, it was found that the human activities play the leading role for PM_2.5.