Large particle penetration through N95 respirator filters and facepiece leaks with cyclic flow.
The aim of this study was to investigate respirator filter and faceseal penetration of particles representing bacterial and fungal spore size ranges (0.7-4 mum). First, field experiments were conducted to determine workplace protection factors (WPFs) for a typical N95 filtering facepiece respirator (FFR). These data (average WPF = 515) were then used to position the FFR on a manikin to simulate realistic donning conditions for laboratory experiments. Filter penetration was also measured after the FFR was fully sealed on the manikin face. This value was deducted from the total penetration (obtained from tests with the partially sealed FFR) to determine the faceseal penetration. All manikin experiments were repeated using three sinusoidal breathing flow patterns corresponding to mean inspiratory flow rates of 15, 30, and 85 l min(-1). The faceseal penetration varied from 0.1 to 1.1% and decreased with increasing particle size (P < 0.001) and breathing rate (P < 0.001). The fractions of aerosols penetrating through the faceseal leakage varied from 0.66 to 0.94. In conclusion, even for a well-fitting FFR respirator, most particle penetration occurs through faceseal leakage, which varies with breathing flow rate and particle size.
Cho
Kyungmin Jacob
KJ
Center for Health-Related Aerosol Studies, University of Cincinnati, Cincinnati, OH 45267, USA.
Reponen
Tiina
T
McKay
Roy
R
Shukla
Rakesh
R
Haruta
Hiroki
H
Sekar
Padmini
P
Grinshpun
Sergey A
SA
D000328:Adult; D000336:Aerosols / Q000032:analysis; D000383:Agriculture; D000395:Air Pollutants, Occupational / Q000032:analysis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D019570:Inhalation Exposure / Q000517:prevention & control; D008348:Manikins; D008422:Materials Testing; D016273:Occupational Exposure / Q000517:prevention & control; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis; D010865:Pilot Projects; D012134:Respiratory Protective Devices; D056152:Respiratory Rate
D000336:Aerosols; D000395:Air Pollutants, Occupational; D052638:Particulate Matter
AMA Arch Ind Hyg Occup Med. 1951 May;3(5):461-78
14829078
Appl Occup Environ Hyg. 2000 Aug;15(8):609-17
10957816
J Occup Environ Hyg. 2007 Sep;4(9):698-707
17654225
J Occup Environ Hyg. 2007 Jun;4(6):420-31
17474032
J Occup Environ Hyg. 2009 Oct;6(10):593-603
19598054
Ann Occup Hyg. 2008 Apr;52(3):177-85
18326870
Am Ind Hyg Assoc J. 1998 Apr;59(4):227-33
9586197
J Occup Environ Hyg. 2006 Sep;3(9):465-74
16857645
J Occup Environ Hyg. 2005 Nov;2(11):577-85
16234218
Front Med Biol Eng. 1993;5(4):265-87
8136313
Ann Occup Hyg. 2005 Apr;49(3):245-57
15668259
Am Ind Hyg Assoc J. 1990 Aug;51(8):420-6
2168122
Ann Occup Hyg. 2008 Jul;52(5):385-96
18477653
Am Ind Hyg Assoc J. 1973 May;34(5):182-92
4517069
Am Ind Hyg Assoc J. 1998 Nov;59(11):796-801
9830088
Am Ind Hyg Assoc J. 1990 Dec;51(12):632-9
2270830
Ann Occup Hyg. 2006 Apr;50(3):259-69
16344291
J Occup Environ Hyg. 2009 Jan;6(1):52-61
19012163