“…Sun Dujuan et al [38] proposed a combined dynamic numerical model of aerosol "sedimentation & diffusion" under the action of gravity, and verified the validity through smoke box experiments. Huang Baokun et al [39] established the deposition model and diffusion model of biological extinction materials, and discussed the influence of flocculent biological particle structure, wind speed and atmospheric stability on the aerodynamic characteristics of biological extinction materials. It was found that under certain conditions, the deposition speed of flocculent biological particles was 50% lower than that of equal volume spherical particles, and the smoke cloud can cover an area of more than 20𝑚 2 .…”