The bigger the membrane the less permeable it is.
The bigger the membrane the less permeable an item is.
Bigger pores means lesser space to diffuse into another body through a partial membrane as it increases in size, so lesser space for particles to go to and fro the membrane, making it less permeable. So, all the dust particles would have harder time filtering through the filter.
When the fracture is closed without shearing and has the same mean aperture, the effect of the fracture size on the hydraulic aperture disappears if the fracture is larger than about 0.2m, since beyond this size the standard deviation of the initial aperture is almost independent of the fracture size. When the fracture is closed after shearing, the hydraulic conductivity shows remarkable anisotropy, which becomes more significant with both shear displacement and closure. However, the relation between the hydraulic aperture normalized by the mean aperture and the mean aperture normalized by the standard deviation of the initial aperture is almost independent of both the fracture size and shear displacement when the shear displacement is less than about 3.1% of the fracture size, at which point the standard deviation of the initial aperture of the sheared fracture is almost independent of the fracture size.