Fig. 1

External mask surface-to-finger virus transfer results, after mask exposure to the simulated environmental aerosols (a), simulated coughing (b) and large droplet spraying (c). For a (simulated environmental aerosols), the column plots show the amount of exhaled viable influenza virus particles (solid bar) and viral RNA (open bar) captured in the aerosols after sampling for 30 min from the air (I), the theoretical maximum amount of virus that should be captured on the mask during 30 min of simulated breathing (II), and the measured amount of virus collected by a finger swipe from the mask surface (III). Column (IV) shows the viral RNA copies detected from the outer layer of the mask. For (b) (simulated coughing), the amounts of viable virus (solid bar) and viral RNA (open bar) detected after finger-swiping of the mask, at exposure from distances of 100 and 200 cm are shown. For (c) (large droplet spraying), the plaque-forming (viable) virus and viral RNA detection, are shown at 20 and 30 °C, at 20, 50, and 70% relative humidities, for each size (100, 200, and 500 μm diameter) of the droplet, at 30 min sampling times. In all figures, the dotted and dashed lines show the minimum detection limits of the plaque-forming and RT-qPCR assays.