Table 2. Quantitative fit testing of reusable masks or respirators and affective factors.
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
|---|---|---|---|
| Anwari et al., 2021 [136] | A novel reusable half-face respirator | Eight different volunteers, including members of the design and testing team (Six males, two females) | Seven out of eight (87.5%) tests passed. Although the Manitoba SSR mask with Intersurgical Hydro-Mini filter obtained the FF of the 108, failed the fit test exercises, including turning side-to-side; 93, talking; 83, and bending; 92 <100. |
| Chichester et al., 2020 [61] | Additively manufactured respirators | ND | Nine separate fit test evaluations were conducted. The AMR equipped with large foam and N95 and P100 filters could provide satisfactory protection (FF≥200) compared to the N95 mask (FF: 189). |
| Fadairo et al., 2020 [36] | Eight brands of half-facepiece and full-facepiece respirators (3M, MSA, North and Moldex) equipped with 3M, North, MSA, Moldex P-100 filters | Mannequin and eight subjects (Six African American males, one African American female, and one Asian male) | There was a significant difference in the results of CNC using the mannequin under ambient and controlled environmental conditions (26319.1 vs. 18382.6, p = 0.0005) in contrast to the CNP results (1679.50 vs. 1879.75, p = 0.7247). While no significant difference was observed in the CNP or CNC for the subjects (p> 0.05). Also, significant differences were observed in ambient and environmental conditions using the mannequin and subjects. |
| Hondjeu et al., 2021 [127] | Duo silicone respirator and 3M N95 respirators (1870+, 1860, 1860S 8210, and 9105S) |
41 HCWs | The passing rates for the 3M N95 disposable and Duo reusable respirators were 58.5% and 100%, respectively. The 3M 1870+ and 8210 respirators had the highest pass rates (78% and 83%, respectively). The harmonic means of the FF for the Duo respirator was higher than for the N95 respirators (2959 vs. 77.4, p< 0.0001). The N95 had a lower passing rate during dynamic maneuvers than stationary maneuvers (61% vs. 73%, p< 0.0001). Also, seven subjects (17.1%) were outside of the NIOSH panel. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Ballard et al., 2021 [142] | 3D-printed prototypes from the rigid (n = 5 designs) and flexible polymers (n = 5 designs), and disposable N95 respirator | Four HCWs | The 3D-printed prototypes with rigid materials did not pass the QNFT procedure. Also, three out of the five prototypes with flexible materials failed the fit test. Only two final 3D-printed prototypes with flexible materials had an overall mean FF of 138 (108–168) compared to the control N95 respirator (FF> 200, p<0.001). |
| Ballard et al., 2021 [53] | N95 respirators (a cloth-based respirator (Sewn Sterilization Wrap), three 3D-printed respirators (P100 Adaptor, Self-Moldable 3D Printed and Multi-Part 3D Printed) and one repurposed from medical supplies (Elastomeric), and 3M 1860 N95 FFR | Seven adult volunteers, including, intended users (HCWs) | Only the EHR equipped with a HEPA filter passed the fit test on both small and large face- standardized users (FF: 110 and 108, respectively). |
| Duda et al., 2020 [46] | Six 3D-printed face mask designs |
Four participants | The PF and TIL values were measured: HSU FM V3: 2.19, 45.69%; HSU FM V4: 2.43, 41.24; Montana mask: 1.72, 58.25%; Maker mask: 1.88, 53.35%; PLA COVID-19 mask: 2.81, 35.71%; TPU COVID-19 mask: 2.33, 43.01%; and Fabric mask: 2.23, 44.78%. |
| Imbrie-Moore et al., 2020 [47] | 3D-printed mask adaptor | Six subjects | All subjects passed the fit testing of the proposed mask. The overall FF was 148>100. |
| Levine et al., 2022 [48] | 3D Printed Masks (Covid Mask Respirator, Low Poly, and Covid-19 Respirator), N95 and a KN95 respirators | Five volunteers (Three males, two females) | The Mask 1, Mask 3, and KN95 respirators had an FF of 52.2, 1.8, and 5.4, respectively. The Mask 2 (Low Poly Low Poly Covid-19 Face Mask Respirator) had a higher FF≥100. All subjects passed the quantitative fit testing of Mask 2 and the N95 respirator. There was no significant difference between the mean FFs for the Mask 2 and the N95 respirators (141.25 vs. 175.60, p< 0.226). |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Liu et al., 2020 [52] | 3MTM re-usable elastomeric respirators equipped with a 3D-printed adaptor | Eight volunteers (Five males, three females) | All volunteers passed the USCs. All eight volunteers passed the fit test. Also, all females were fitted with the 3M 7501 (small) respirator. |
| Manomaipiboon et al., 2020 [116] | Silicone VJR-NMU N99 half-piece respirator | 41 HCWs (21 males, 20 females) | 32 (78%) subjects passed the first fit test. After tightening the O-ring trap, seven subjects passed the fit test (77.8%). Five subjects passed the third fit test (80%). The overall fit test passing rate was 40/41 (97.6%). One subject failed, even after adjusting the strap for the third time. |
| Martelly et al., 2021 [129] | A Reusable, Hot Water Moldable, Additively Manufactured Mask | 13 subjects (Six males, seven females) | There was an improvement in fit between the unmolded and molded masks (7 ± 17 vs. 143 ± 62). The molded mask had a passing rate of 77% (10 out of 13). |
| Meadwell et al., 2019 [143] | Nine designs of elastomer | One human subject | The pressure testing performed well; however, it could not be substituted by robust fit testing. The highest FF obtained by continuous ribs-soft elastomer (18.51; 1129/61). |
| McLeod et al., 2021 [124] | 3M EHR model 6000 | Mannequin | The FFs were highest for the EHRs with two layers of 7093 3M NIOSH P100 Particulate Filter was 2281, and two layers of P100 3M 2097 NIOSH were 1678. The FF for the combinations of Super-calendered Final Product (1 ply)-Side overhang and P100 3M 2097 NIOSH was 341. The FF for the combinations of uncalendered Final Product (2 ply)-Side overhang and P100 3M 2097 NIOSH was 215. |
| Ng et al., 2020 [112] | The reusable silicone-molded face mask (SSM) | 40 HCWs (20 males, 20 females) | The mean harmonic FFs for the N95 respirator and SSM were 137.9 and 6316.7, respectively. The overall passing rates for the mentioned masks were 65% and 100%, respectively. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Roche et al., 2022 [51] | Personalized 3D-printed respirator | 50 HCWs (21 males, 29 females) | In the control group, 38 subjects passed and 12 failed the FFP3. In the test group, 44 passed and six failed the 3D-printed respirator. 11 subjects who failed the FFP3 passed the 3D-printed respirator. Conversely, five who passed the FFP3 failed the 3D-printed respirator. No significant difference was found in the fitting rate of both respirators (170 vs. 180, p = 0.21). |
| Chughtai et al., 2020 [162] | CleanSpace™ lightweight tight-fitting half-facepiece PAPR | 20 HCWs including nursing and medical staff (13 males, seven females) | All participants passed the fit test with a GM FF (GSD) of 6768 (3755). |
| Germonpre et al., 2020 [58] | Snorkel Masks | Staff of Belgium Hospitals (HCWs) |
The modified snorkel masks had high FFs. Subea A: 58, Subea B, C: 200+, Subea D: 200++, Subea E: 52, Seac: 200+, Aqualung:117, Cressi: 157, Ocean Reef A:57, Ocean Reef B, C, D, and E: 200+, and 3M Aura 9322+ FFP2: 62. |
| Greig et al., 2020 [141] | Modified full-face snorkel mask | One male user | The novel mask failed the fit test despite passing the USCs. Then, it was considered that the QNFT procedures was required for the full-face mask. |
| Greig et al., 2022 [85] | Full-face snorkel mask | 16 clinical staff (Seven males, nine females) | One fit test considered a pass when a P3 was mounted with an uncoated adaptor to a snorkel mask (FF: 564). No subjects passed using the coated adaptor. All subjects who used the HME filter failed the fit test (median (IQR) FF: 8 (3–23)). The coated P3 adaptors had a higher median (IQR) FF than the uncoated P3 ones (899 (350–1396) vs. 349 (169–462)). |
| Grinshpun et al., 2020 [163] | Three makes and models of respirators, N95 FFR, P100 FFR, and half-mask elastomeric facepiece (11 respirators) | 25 adult subjects (9 males, 16 females) | The AccuFIT 9000 could identify poor-fitting respirators with a sensitivity of 0.95, a specificity of 0.97, and a Kappa of 0.92. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Harmata et al., 2022 [164] | Three Full-face piece gas respirators, including MP-5, MP-6, and Promask | Ten participants | The FFs were for the MP-6 mask, 1460, for the MP-5 mask, 950, and for the Promask mask, 850, were obtained. The FFs for the MP-6 masks three days, the MP-5 mask, and the Promask after two days reached <10000. |
| Kechli et al., 2020 [60] | Full-face snorkel mask | ND | The modified full-face snorkel mask had an overall FF of 142. The only talking exercise had an FF of 94< 100. |
| Kroo et al., 2021 [165] | Modified Full-Face Snorkel Masks (Pneumask) | Three volunteers | All three subjects passed the QNFT procedure. |
| Nicholson et al., 2021 [144] | Ocean Reef Aria full face snorkel masks (medium/large, small/medium, large/extra large), and S/M full-faced snorkel masks | One user | The FFs of the 3M 6800 full-face respirator, Snorkel mask with a duct tape, Snorkel mask with no modifications, and snorkel mask with a mouth cover remove were 333867, 32281, 15448, and 1105, respectively. |
| Persing et al., 2021 [166] | 3M HER with P100 (OV) cartridges model 65021HA1 | A single member of the research team | The LPFs for the DC CPC and PortaCount were similar, while the DC OPC was different from PortaCount. The LPFs of the PortaCount was 89, DC CPC was 77, and DC OPC was 156, per the target LPF of 100 against the Sodium chloride aerosol and 370, 330, and 961, respectively, per the target LPF of 300 against the Sodium chloride aerosol. |
| Pettinger et al., 2021 [63] | Three respirators, including FFP2 respirator, Anaesthesia Face Mask (AFM), and full-face Modified Snorkeling Mask (MSM) |
Ten HCWs, including anaesthesiology residents (Five males, five females) |
The seal check failure rates for the FFP2 (control) were 37 (41%), 10 (11%) for the AFM, and 6 (7%) for the MSM. There was no significant difference among the FFs of the studied respirators. The fit test passed rates for the FFP2 (control) were 5 (50%), 8 (80%) for the AFM, and 7 (70%) for the MSM, p = 0.69. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Bergman et al., 2019 [167] | Six respirators, including three families of full-facepiece respirators, including a one-size-only family, a two-size family, and a three-size family equipped with P-100 filters | 25 subjects | The PPR was more than 75%. One of two donning achieved the FF of 500. The PPR for the three-size, two-size, and one-size families were 100, 79, and 88%, respectively. The PPR decreased with increasing FFs of 500, 1000, and 2000. |
| Chehade et al., 2021 [168] | Two masks, including assembled mask Hans Rudolf full-face mask & Respironics Performax full-face mask | 20 volunteers from Oklahoma City Veteran Affairs Health Care System (10 males, 10 females) | All participants passed the test with the GM±GSD of 2317±3.8. |
| Han et al., 2022 [99] | Three types of respirators, including N95, half-facepiece mask, and full-facepiece mask | 50 volunteer college students (25 males, 25 females) | There was a high correlation between two fit testers (p< 0.00001). The FF of 100 per N95 respirator determined by PortaCount equalized to the FF of 75 by SIBATA MT. There was very high consistency between two devices for half- and full-facepiece respirators, which both satisfied the values specified by the ANSI standard. But the N95 respirator did not meet the ANSI requirement. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Rengasamy et al., 2021 [169] | NIOSH-approved elastomeric half-facepiece, full-facepiece, and PAPRs with respirators tight-fitting and loose-fitting facepiece |
16 subjects | The FFs were obtained for the MSA EHR: 1507, North EHR: 1667, MSA Full-facepiece: 4670, North Full-facepiece: 7753, PAPR-tight fitting; MSA: 7731, Bullard: 3799. Also, the TILs for the MSA EHR for corn oil aerosol were significantly larger than for NaCl aerosol (0.197 vs. 0.056) and for the North EHR (0.086 vs. 0.038). However, the TILs for the NaCl aerosol were significantly larger than for corn oil aerosol per the PAPRs but not per the full-facepiece respirators, including the MSA PAPR-tight fitting (0.010 vs. 0.003), Bullard PAPR-tight fitting (0.011 vs. 0.002), 3M PAPR-loose-fitting (0.013 vs. 0.003), Bullard PAPR-fitting (0.015 vs. 0.002), MSA Full-facepiece (0.046 vs. 0.049), and 3M Full-facepiece (0.015 vs. 0.016). |
| Sietsema et al., 2022 [106] | NIOSH-approved Envo quarter facepiece elastomeric respirator | 25 HCWs of Rush University hospital (14 males, 11 females) | The median (5th and 95th percentile) FF was 188 (48, 201), SWPF-truncated SWPF was 181 (94, 199), and non-truncated SWPF was 570 (153, 1508). |
| Weng et al., 2022 [170] | Novel full-face mask | 18 participants, (Eight males, 10 females) | The mask could provide acceptable protection. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Clinkard et al., 2021 [69] | N95, snorkel masks with high-efficiency filters and snorkel masks with powered-air purifying respirators |
51 HCWs (24 males, 27 females) | 59% and 20% of participants failed at one or more fit test exercises using the N95s and snorkel masks with high-efficiency filters, respectively. 24% and 12% of the subjects failed the overall FFs of N95 and snorkel masks with high-efficiency filters. The mean FF for snorkel masks with a PAPR (12177) and snorkel masks with a high-efficiency filter (2939) was significantly higher than that of the N95 mask (144), p< 0.05. The passing proportions of the N95 respirator (65%) and snorkel mask with a high-efficiency filter (92%) were lower than those of the snorkel mask with PAPR (100%, p< 0.01). |
| Convissar et al., 2020 [35] | Modified Airway from VEntilatoR Circuit (MAVerIC) | One anesthesia provider | The cost-benefit quantitative fit testing procedure consisted of Bag valve mask (an Ambu bag) with a pressure manometer was carried out using the MAVerIC. |
| Toigo et al., 2021 [67] | Aria Ocean Reef® full-face snorkeling mask | 71 HCWs, including nurses, respiratory therapists, physicians, residents, patient attendants, technicians, and care advisors |
Four out of 71 subjects underwent the QNFT, and all of them passed. 55 out of 67 conducted fit tests and passed the QLFT. 83.1% of the subjects who could not pass the fit testing of medical respirators passed the fit testing of the snorkel mask. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Cass et al., 2022 [93] | Two N95 respirator brands and CleanSpace HALO® powered air-purifying respirator |
189 ICU staff members, including doctors, nurses, allied health professionals, and support staff member (61 males, 128 females) | Fit testing failure rates were 18/60 (30.0%) for the 3M and 33/107 (30.8%) for the Halyard. The passing fit test rate increased from 88/189 (46.6%, 95% CI, 39.3–53.9%) on unassisted fitting to 105/189 (55.6%, 95% CI 48.2–62.8%) after the provision of assistance on the first respirator type worn and 131/189 (69.3%, 95% CI ¼ 62.2e75.8%) per the second respirator type. Fifty-eight of 189 (30.7%, 95% CI, 24.2–37.8%) failed on both N95 respirator types, and 47 (100%) subjects proceeded to and passed the fit testing on CleanSpace HALO® PAPR. |
| Baba et al., 2022 [104] | Replaceable particulate respirators (RPRs) Chiyoda model 1180–05 and PAPR Chiyoda model BL–321S. | Ten participants from University of Occupational and Environmental Health (Eight males, two females) | The passing rate and mean FFs of both RPR (i.e., RPR-H: at resting state 3 and at exercise state: 2 out of 10 subjects, 68.2 vs. 118.7) and PAPR (i.e., PAPR-R: at resting state 10 and at exercise state: 9, 786.5 vs. 444.5) obtained from the exercising tasks were higher than the resting state (p<0.001). But the PAPR provided satisfactory protection (FF> 100). |
| Grinshpun et al., 2020 [122] | 3M Versaflow, TR-300+ PAPR | Ten human subjects and manikin | The MPF was measured ranged from 5000–10000. The SWPF ranged from 3000–10000. A near-perfect correlation was observed between two methods (0.997). There was a high correlation between RePM and CPC in measuring different particle size ranges. High sensitivity (96.3%) and specificity (100%) achieved on human subjects at a response time of 60 sec. |
| Kessel et al., 2022 [110] | PAPR | One HCW (A rural healthcare provider) | The helmet equipped with two layers of H600 filter media had the highest FF of 2229 against NaCl and 28942 against SiO2. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| McGrath et al., 2022 [86] | Bubble-PAPR | 15 clinical and non-clinical staff (Five males, 10 females) | Ten subjects passed the fit test. The mean FF was 16931> 500. |
| Nagel et al., 2021 [50] | 3D printable PAPR | Two subjects | The novel PAPR obtained the FF of 1362≥500 using the PortaCount. |
| Goto et al., 2021 [79] | Tight-fitting PAPR (BL-321H half-mask respirator and a BLA-62; KOKEN LTD filter) | Fifty-four HCWs, including doctor, nurse, and others HCWs (33 males, 21 females) | 42 (78%) of the subjects failed at least one of the three sessions of chest compression (SWPF <500). 39 (72%), 30 (56%), and 25 (46%) failed in the first, second, and third sessions, respectively. The median (IQR) for overall SWPF was 4304 (685–16191). Therefore, tight-fitting PAPR could not provide adequate protection. |
| Ng et al., 2023 [135] | HALO PAPR | Eight HCWs (Four males, four females) | The mean FF was higher than 1000. There were no significant differences before, during, or after the chest compression. The FFs were when power off: 1869 (617–4333), 1748 (378–6881), and 1243 (669–3881), respectively and when power on: 3576 (2128–6109), 4290 (2048–4931), and 4135 (2913–6890), respectively. |
| Rees et al., 2021 [171] | PAPR | Five subjects (Three males, two females) | The mean FF for the PAPR was 1851 (277). The FF was not reduced during the speech, and there were exaggerated maneuvers. It is required that PAPR be equipped with a powered pack to ensure protection for the users. |
| Sekoguchi et al., 2020 [103] | BL-321S Koken Ltd. PAPR with tight-fitting and half-facepiece respirator | Ten subjects of University of Occupational and Environmental Health (Eight males, two females) | The leakage rate for the RPR was 1.82–10.92% (FF: 9.16–54.94) and 0.18–0.42% (FF: 238.10–555.55) for the PAPR. The performance of the RPR decreased, while the performance of the PAPR was not significantly different. |
| Study | Respirator Features (Brand, model, size, style) | Subject Characteristics | Findings |
| Sekoguchi et al., 2022 [101] | Two respirators, including SHIGEMATSU WORKS DR77SR2 and SHIGEMATSU WORKS Sy11G2 PAPR | Eight men workplace participants | The GM ±SD WFPs for the C-RPR, U-RPR, and PAPR were 17.7±2.59, 27.0±3.86, and 117.3±5.25. |
| Temmesfeld et al., 2022 [125] | Novel PAPR | Six subjects (One male, five females) and one mannequin | The TIL for the surgical helmet with a PAPR filter adaptor using a mannequin did not exceed 0.07% (FF: 1428.57) for any particle size at any time of the 23-minute-lasting loading cycle. Also, the mean and maximum TIL obtained from testing on subjects were 0.00465% (FF: 21505.38) and 0.00759% (FF:13175.23), respectively. |
| Rowlett et al., 2021 [54] | Elastomeric half-mask respirators | 327 ASSPs | 90% of the participants were familiar with the QNFT procedures. Only a significant difference was found in the perceived accuracy of the QNFT by level of experience (p = 0.006). |
| Xu et al., 2023 [45] | Four MSA Safety respirators, including two half masks (410 and 420 air-purifying respirators) and two full masks (3S air-purifying respirator and Ultra Elite SCBA) | 225 chemical plant operators and maintenance and laboratory personnel | The passing rates were 88.1% for males and 75.6% for females. Most females donned small size respirators due to thin face and sharp chin. Gender had a significant effect on fitting (X2 = 5.186, p = 0.023). Other factors had not significant influence on respirator fitting. The half-masks had lower passing rate than the full-masks (84.7 vs. 91.6%, p< 0.05). The 410 and 420 models of APRs (81.6% vs. 86.5%, respectively). The passing rate for 3S APR was 90.0% and for Ultra Elite SCBA was 95.2%. |
| Rowlett et al., 2021 [54] | Elastomeric half-mask respirators | 327 ASSPs | 90% of the participants were familiar with the QNFT procedures. Only a significant difference was found in the perceived accuracy of the QNFT by level of experience (p = 0.006). |
Note:
FF: Fit Factor
QNFT: Quantitative Fit Test
HCWs: Healthcare workers
AMR: Additively manufactured respirators
IQR: Interquartile Range
CNC: Condensation Nuclei Counter
CPC: Condensation Particle Counter
CNP: Controlled Negative Pressure
HEPA: High Efficiency Particulate Air Filter
NIOSH: The National Institute for Occupational Safety and Health
SSM: silicone-molded face mask
GM±GSD: geometric mean+ geometric standard deviation
PAPR: powered air purifying respirator
JIS: Japan Industrial Standard
RPRs: Replaceable particulate respirators
TIL: Total Inward Leakage
SWPF: simulated workplace protection factor
MAVerIC: Modified Airway from VEntilatoR Circuit
S/M: small/medium
MSM: Modified Snorkeling Mask
AFM: Anaesthesia Face Mask
ICU: Intensive care unit
EHRs: elastomeric half-facepiece respirators / reusable facepiece respirators
APR: air-purifying respirator
SCBA: self-contained breathing apparatus
ND: Not determined
ASSP: American Society of Safety Professionals
USCs: User Seal Checks