Filtration of Cigarette Smoke: Relative Contributions of Inertial Impaction, Diffusional Deposition, and Direct Interception

The results of this analysis suggest that a filter geometry which will allow smoke to pass at a Iower than normal velocity is desirable to improve filter efficiency. This improved efficiency is due to the major contribution of the diffusion mechanism and the insignificant contribution of the impaction mechanism to the filtration process. Lower than normal velocities wilI also reduce the pressure drop. If a filter can be designed to operate at a lower velocity, and therefore at a lower pressure drop, it is desirable to have the acetate filaments oriented perpendicularly to the flow direction of the smoke. This geometry gives higher removal per unit weight of acetate than the geometry of a conventional filter.