Quantification and influence factor analysis on total inward leakage of N95 respirators by simulating healthcare professional’s procedures

Respiratory protection is critical to minimize airborne infection risk for healthcare workers. The main factor affecting infection risk in the medical scenario is leakage between the respirator and the healthcare workers’ face. However, it is difficult to quantify the effectiveness of respirators due to the numerous influencing factors. The medical activities were simulated by the fitting test, and the inverse of the results were used to get the total inward leakage of respirators. 114 subjects were divided according to gender, profession, age, risk area, and BMIs, participated in fitting test of four N95 respirators. The result showed that the value range of total inward leakage for tested N95 respirators was between 0.50% and 2.39%. Flat-folded respirators were more prone to leakage than cup-shaped ones, so it was essential to account for the impact of respirator shape. Similarly, this study found that gender and profession had no significant correlation with total inward leakage. Some medical procedures include bending, and turning head from side to side, or up and down, which had a significant influence on the protective efficacy of the N95 respirator. Facial dimensions and BMI exerted a more pronounced influence on the protective efficacy of the N95 respirator, and they were in the correlations. Healthcare personnels wore a well-fitting N95 respirator properly for excellent protection, reducing occurrence of nosocomial infections and occupational exposures, and optimizing respiratory protection strategies.