"Health Considerations[edit] The additional cost burden of DPF filters is primarily passed to consumers with possibly the only benefit being quieter trucks. Any reduction in overall soot by mass, aka diesel particulate matter (DPM), may be negated by the mostly-ignored fact that DPM from DPFs is extremely fine, finer than the DPM that is released from pre-DPF diesel engines.[citation needed] The finer DPM is estimated to have more surface area and penetrate lung tissue more easily than larger particles. No healthy human studies have been performed at diesel exhaust concentrations normally found in an urban or city environment, eliminating other health contributing factors to disease would be insurmountable in such a study.[11]"
