Characterizing odor adsorption on dust surface based on age and size distributions of airborne dust in a ventilated airspace

A mathematical model characterizing the adsorption of odor on the surface of airborne dust in a ventilated airspace is derived based on the concept of homogeneous surface diffusion of a complete mixing airflow system. The main scheme of the paper is to incorporate the age and size distributions of airborne dust into the diffusion model for evaluating the odor adsorption on the ambient aerosol. A closed-form solution is presented here to allow a series of numerical experiments for investigating the effects of adsorption characteristics, the mean age of airborne dust, surface effective diffusivity, and dust particle size on the adsorption of odor to the existing aerosol. Results obtained show that the most favorable performance of a ventilation system in reducing odor concentrations is when the system model is operated under r_p/√D_sτ̄<1, in which r_p is the radius of an airborne dust, D_s is the effective diffusivity of bulk odor in air, and τ̄ is the mean residence time of airborne dusts in ventilated airspaces. The rate of adsorption of the odor to the existing ambient aerosol is also presented. The model enables engineers for evaluating the performance of the ventilation systems in reducing the odor emitted from stored manure in animal housing and can be used in the future to design the deodorization processes of a biofilter.