Particle Size-Selective Assessment of Protection of European Standard FFP Respirators and Surgical Masks against Particles-Tested with Human Subjects

Abstract

This study was conducted to investigate the protection of disposable filtering half-facepiece respirators of different grades against particles between 0.093 and 1.61 μm. A personal sampling system was used to particle size-selectively assess the protection of respirators. The results show that about 10.9% of FFP2 respirators and 28.2% of FFP3 respirators demonstrate assigned protection factors (APFs) below 10 and 20, which are the levels assigned for these respirators by the British Standard. On average, the protection factors of FFP respirators were 11.5 to 15.9 times greater than those of surgical masks. The minimum protection factors (PFs) were observed for particles between 0.263 and 0.384 μm. No significant difference in PF results was found among FFP respirator categories and particle size. A strong association between fit factors and protection factors was found. The study indicates that FFP respirators may not achieve the expected protection level and the APFs may need to be revised for these classes of respirators.

Performance Evaluation of Full Facepiece Respirators with Cartridges

“…However, the same as Grinshpun's et al (2009) study, we performed expiratory air dehydration and thereby eliminated that possibilities of particle size and concentration changes due to hydroscopicity. The geometric mean (GM) of PFs of FFRs in this study was 97, which was higher by 3.6-4.9 folds than that indicated in EN-specified FF1 (GM = 19.6), FFP2 (GM = 27.1) or FFP3 (GM = 26.7), and higher by 57 folds than that of surgical masks (GM = 1.7) (Lee et al, 2016). It was also higher by 4.5 and 40 folds than that of N95 filtering facepiece respirators (GM = 21.5) or that of surgical masks (GM = 2.4) in another study (Lee et al, 2008).…”

“…Detailed layout, particle generation and control methods of subject test chamber were described in our previous study (Lee et al, 2016), and a PortaCount® Plus (TSI Inc., St. Paul, MN, USA) was used to conduct fit factors determination.…”

“…3) to collect particle concentrations from inside and outside of the respirator by using previous studies as references (Lee et al, 2004;Lee et al, 2005;Lee et al, 2008). The prototype of this sampling system had been used in our previous study to measure PFs of EN-specified FFP respirators and surgical masks (Lee et al, 2016). The novel model was equipped with two sampling lines that could be used to collect NaCl particles inside and outside of the respirator, respectively.…”

“…Two minutes of particle concentrations outside of the respirator should also be collected before and after the activities, and the average was considered as the average particle concentration outside of the respirator during activity. Please refer to the study of Lee et al (2016) for detailed PF calculation.…”

“…Because real workplace protection factors were very difficult to measure or obtain, NIOSH proposed a concept of total inward leakage test in 2004 (NIOSH, 2004b) to evaluate the sum of air leakage from the filter, faceseal leaks, or other places of the respirator (e.g., exhalation valve or crack) in respirator wearers. Our previous studies also used the same concept and successfully evaluated performance of N95 filtering facepiece respirators, surgical masks and FFP series respirators (Lee et al, 2008;Reponen et al, 2009;Lee et al, 2016). There were only studies investigating breakthrough time of hazardous gases, particle penetration through filters, or percentages of exhalation valve leakage in FFRs.…”