Study on the relationship between the fitness of three types of N95 respirators and facial dimensions.

N95 respirators are the core equipment used by healthcare workers to prevent the spread of respiratory diseases. The protective effect of N95 against infection spread depends on the fit of the N95 to the wearer, which is related to the wearer's facial dimensions. The purpose of this cross-sectional study was to assess the relationship between the fit of three types of N95 and facial dimensions. A total of 305 healthcare workers from ten hospitals in Beijing were recruited for this study. Facial dimensions of workers were measured using Intel RealSense Depth Camera D435. Fit testing was conducted on three types of N95 using the TSI-8038 Porta Count Pro + Respirator Fit Tester. Possible associations between the fit test results and facial dimension data were examined. A Porta Count reading of 100 was used as the criterion for an acceptable fit. The fit of the folding respirators was positively correlated with nose length ( = 0.13,  = 0.02), nose height ( = 0.14,  = 0.02), and face width ( = 0.12,  = 0.03), whereas that of flat respirators was correlated with nose width ( = 0.16,  < 0.01), chin length ( = 0.18,  < 0.01), and pro-face width ( = 0.13,  = 0.02), and that of arched respirators was correlated with the nose length ( = 0.13,  = 0.03). The fit of N95 for wearers depends on their facial features. The results of this study can provide advice for medical workers to choose the appropriate N95. Medical staff should fully consider their facial dimensions when choosing an appropriate N95 to improve the protective efficacy of respirators and to reduce the risk of infection by respiratory diseases.