A system and method for manufacturing a filter includes a filamentary material delivery apparatus, a support structure for supporting a continuous stream of filamentary material, and a particle distribution apparatus. The particle distribution apparatus includes an apertured distribution belt positioned above the support structure and in communication with an outlet of a particle storing hopper. The belt defines a plurality of spaced openings through which particles are distributed onto the continuous stream of filamentary material to form a particle-bearing stream of filamentary material.