Abstract: The change in particle filtration efficiency (PFE), bacterial filtration efficiency (BEF), and respiratory resistance of surgical masks over actual wearing time were reported in this paper to provide guidance for the public to use masks rationally and efficiently during the outbreak of respiratory infectious diseases. Two types of surgical masks conformed with YY 0469-2011 Surgical Mask standard were selected for the tests. 40 adult volunteers were divided into two groups randomly to wear these surgical masks for 4 h, 10 h, 24 h, 32 h, and 48 h, respectively. And then the protective efficiency of the masks was tested within 1 h after wearing them. The results showed that the protective efficiency of these two surgical masks all declined significantly with the prolongation of wearing time. Thereinto, after 32 h of wearing, the PFE of the masks was still over 60%, which was far higher than the standard requirement (30%). After 10 h of wearing, the BFE of both masks could still be 96.8%. Based on the above results, the optimal time of medical surgical masks in medium or high-risk areas of coronavirus exposure should not exceed 10 hours; for low-risk areas, the wearing time can be extended to 24 hours.

Key words: surgical mask; actual wearing time; particle filtration efficiency; bacteria filtration efficiency