Intranasal, hollow, cylindrical, medical grade and silicone stent with two outer layers face mask filters at both ends was proposed for atmospheric suspended particulate matter prevention. The personal respiratory protective device efficacy was done at the Otolaryngology Department, Ramathibodi Hospital from April 1996 to October 1997. Single pulse mode of carbon dioxide laser smoke particle was the suitable source of atmospheric suspended particulate matter. A laser plume evacuator removed laser smoke particles with 5 Millipore filters of 0.22 um pore size or 5 intranasal stent with filters attached at the inlet end. A Millipore filter got the same laser smoke particle amount that passed through each intranasal stent filter with an air flow rate of 15 l/min controlled by a rotameter. Laser smoke particle deposition in filter materials was counted under a high power optical microscope. Laser smoke particle amount in each layer of a four-layer filter of intranasal stent with 7.5, 15.0 and 30.0 l/min air flow rates is shown. The filtration efficacy of four, three and two layers of intranasal stent with a filter for laser smoke particle retention were compared. An intranasal stent with filter could be applied in a human nasal vestibule with acceptable air flow resistant during public transportation in a traffic congested area.