Apparatus and methods are disclosed which apply inorganic particles to a plugged honeycomb body comprising porous walls, an inlet end and an outlet end. The apparatus comprises a Venturi tube through which the particles flow into a duct system. Filtration articles comprise: a plugged honeycomb body; inorganic deposits disposed within the plugged honeycomb filter body having a porosity in a range of greater than 95% to less than or equal to 99.9% and an average thickness in a range of greater than or equal to 0.5 µm to less than or equal to 50 µm; and a clean filtration efficiency of greater than or equal to 85% as measured by a smoke filtration efficiency test.