A process for the on line production of cigarette filters comprises the steps of conveying a continuous thin flexible substrate past a source of smoke altering particulate material, such as adsorbents, catalysts and flavorants. An electrostatic charge is applied onto the substrate upstream of the source of particulate material. A layer of particulate material from the source is deposited onto the substrate with the thickness of the layer depending upon the strength of the electrostatic charge. The coated substrate is then cut into pieces, and the pieces are placed into the cavities between spaced apart filter components. In an alternative process, filter paper is coated with smoke altering particulate material by electrostatic deposition techniques, and spaced apart filter components are placed onto the particulate coated filter paper which is then folded around the filter components.