Purpose: Frontline health care workers (HCWs) must wear a standard N95 or FFP2 respirator during worldwide pandemics of respiratory diseases including COVID-19 to protect against airborne infectious pathogens when performing care activities . This study aimed to quantitatively investigate the fit of most of the common FFRs used during the COVID-19 pandemic in Iran .
Methods: A total of 37 volunteers were fit tested in 20 selected FFRs in a randomized order . The selected FFRs were underwent quantitative fit testing by PortaCount® model 8038 . To determine the effects of face sizes on respirator fit, the participants' facial dimensions were measured using a digital caliper .
Results: The rate of passing fit tests for the studied FFRs were surprisingly low with 11 out of 20 FFRs having less than 10% passing fit tests and the best performers having only 43% and 27% passing fit tests (brands 2 and 20, respectively). Cup-shaped respirators provided significantly greater fit than the vertical flat-fold ones (p <0.001). A significantly different FFs were found among the respirator brands (F = 13.60, p <0.001). Conclusion: Overall, unacceptably low fit factors were obtained from the studied FFRs . The main reasons for this are suspected to single size and style for each studied FFR . It confirms the importance and requirement of the proper respirator selection in that way fitted optimally into facial dimensions, appropriate usage, and properly performing the fit testing procedure . A unique fit test panel should be developed to guide respirator wearers in selecting the appropriate FFR for their specific face sizes.