Figures (5)  Tables (1)

    • Figure 1. 

      Three main factors in indoor airborne transmission of respiratory infectious diseases: Source of infection, airborne transmission route, exposure risk assessment.

    • Figure 2. 

      The 'enhancement effect' of human movement on the high-risk range[99].

    • Figure 3. 

      Multi-person movement's effects on airborne transmission[124].

    • Figure 4. 

      Model of facemask protection. Source control aims to reduce virus-laden droplets exhaled from infected individuals, and respiratory protection aims to protect susceptible individual from inhaling droplets emitted by infection sources.

    • Figure 5. 

      Synthetic schlieren images of exhaled flows changes with and without a facemasks under different scenarios: (a), (d) breathing quietly; (b), (e) saying 'also'; (c), (f) laughing[136].

    • RegionRegulationNameParticle Filtration
      Effciency (PFE, %)      		FE test flowrateParticle diameter (µm)
      ChinaGB2626-2019KN90≥ 9030~100 L/min, continuous flow0.075 ± 0.020
      KN95≥ 95
      KN100≥ 99.97
      EuropeEN 149-2001+A1: 2009FFP1≥ 8095 L/min, continuous flow0.02~2
      FFP2≥ 94
      FFP3≥ 99
      AmericaNIOSH 42 CFR Part 84-2019N95≥ 9520.0~65.0 L/min, breathing0.075 ± 0.020

      Table 1. 

      High-performance respirator regulations.