Abstract: A filter and method for applying differential levels of active ingredient materials to specific areas of filters, such as the filter paper used to make disposable vacuum cleaner bags, so as to cause the effluent such as air which has passed through such filters to sustainably act as a dispersing agent for such filter-impregnated active ingredients as may condition the effluent which has passed through the filter in ways that are desirable to the user of the filter. The active ingredients are unevenly distributed on the filter substrate in a pattern determined by predicted changing flow rate patterns through the area of the substrate during intervals of increasing accumulation of particulate matter against the filter and effective to maximally sustain dispersion of active ingredients during such intervals.