title: Respirator Performance against Nanoparticles under Simulated Workplace Activities.
abstract: Filtering facepiece respirators (FFRs) and elastomeric half-mask respirators (EHRs) are commonly used by workers for protection against potentially hazardous particles, including engineered nanoparticles. The purpose of this study was to evaluate the performance of these types of respirators against 10-400 nm particles using human subjects exposed to NaCl aerosols under simulated workplace activities. Simulated workplace protection factors (SWPFs) were measured for eight combinations of respirator models (2 N95 FFRs, 2 P100 FFRs, 2 N95 EHRs, and 2 P100 EHRs) worn by 25 healthy test subjects (13 females and 12 males) with varying face sizes. Before beginning a SWPF test for a given respirator model, each subject had to pass a quantitative fit test. Each SWPF test was performed using a protocol of six exercises for 3 min each: (i) normal breathing, (ii) deep breathing, (iii) moving head side to side, (iv) moving head up and down, (v) bending at the waist, and (vi) a simulated laboratory-vessel cleaning motion. Two scanning mobility particle sizers were used simultaneously to measure the upstream (outside the respirator) and downstream (inside the respirator) test aerosol; SWPF was then calculated as a ratio of the upstream and downstream particle concentrations. In general, geometric mean SWPF (GM-SWPF) was highest for the P100 EHRs, followed by P100 FFRs, N95 EHRs, and N95 FFRs. This trend holds true for nanoparticles (10-100 nm), larger size particles (100-400 nm), and the 'all size' range (10-400 nm). All respirators provided better or similar performance levels for 10-100 nm particles as compared to larger 100-400 nm particles. This study found that class P100 respirators provided higher SWPFs compared to class N95 respirators (P < 0.05) for both FFR and EHR types. All respirators provided expected performance (i.e. fifth percentile SWPF > 10) against all particle size ranges tested.
authors.affiliation: National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA; Eav8@cdc.gov.
authors.forename: Evanly
authors.initials: E
authors.lastname: Vo
authors.affiliation: National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA;
authors.forename: Ziqing
authors.initials: Z
authors.lastname: Zhuang
authors.affiliation: URS Corporation, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Horvatin
authors.affiliation: National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA;
authors.forename: Yuewei
authors.initials: Y
authors.lastname: Liu
authors.affiliation: National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA;
authors.forename: Xinjian
authors.initials: X
authors.lastname: He
authors.affiliation: National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236, USA;
authors.forename: Samy
authors.initials: S
authors.lastname: Rengasamy
mesh_terms: D000328:Adult; D000336:Aerosols / Q000032:analysis; D000368:Aged; D000395:Air Pollutants, Occupational / Q000032:analysis; D004867:Equipment Design; D005260:Female; D005374:Filtration / Q000295:instrumentation; D006801:Humans; D019570:Inhalation Exposure / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D053758:Nanoparticles; D009314:National Institute for Occupational Safety and Health, U.S. / Q000592:standards; D016273:Occupational Exposure / Q000517:prevention & control; D010316:Particle Size; D012134:Respiratory Protective Devices / Q000592:standards*; D014481:United States; D017132:Workplace
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational
keywords: N95 respirators; P100 respirators; elastomeric half-mask respirators; filtering facepiece respirators; nanoparticle; simulated workplace protection factors