Challenge of N95 and P100 Filtering Facepiece Respirators with Particles Containing Viable H1N1

Abstract

Abstract : 3M1860s (N95) and 3M 8293 (P100) NIOSH-approved filtering facepiece respirators (FFRs) were challenged with aerosolized particles of H1N1 influenza to measure the amount of viable influenza virus that penetrates each device. The test was conducted at the NIOSH-recommended flowrate of 85 LPM using guidance provided by a Department of Defense test standard developed for challenging air purification devices with viable microbial aerosols. The count mode diameter (CMD) particle size of the challenge aerosol was approximate 0.8 microns, which was created by aerosolizing H1N1 influenza virus in an artificial saliva buffer using the Laboratory-Scale Aerosol Tunnel (LSAT). In addition to the H1N1 challenge, each FFR was also challenged with 0.8- microns inert beads. In these tests the N95 FFR (n = 3) removed 99% of the viable H1N1 from the air stream and the P100 (n =3) removed 99.99% of viable H1N1 from the airstream. The percent reductions in mechanical and viable particle counts measured for each FFR using the 0.8- microns bead challenge were equivalent to the percent reduction values measured for like-sized particles containing H1N1, verifying that bioaerosols act as typical particles. These data demonstrate that the N95 and P100 FFR will reduce viable H1N1 aerosol from the airstream at greater than or equal to their rated value.