Time evolution of physical properties and their impact on grain size in the hot component. Left: evolution of density (blue) and temperature (red) of the tracer particle selected to represent the hot component. Middle: dust size distribution at several snapshots. Right: time evolution of the total adsorption surface (blue solid line) and average grain size (red solid line). Also shown are the default NAUTILUS values for the total surface (blue dashed line) and average grain size (red dashed line) used in the chemical analysis presented in Sects. 4 and 5.