Figure 3.

Particle concentration (aerodynamic diameter 0.52–20 μm) exhaled from the respiratory tract during coughing, deep breathing, normal breathing, and talking and divided into particles with an aerodynamic diameter greater than 1 μm (top chart) and less than 1 μm (bottom chart). There appears to be a difference in the number and diameter of particles with different respiratory maneuvers, when stratified by particle size. Coughing and deep breathing appear to generate a larger number of particles less than 1 μm than normal breathing or talking. FM = 15 L/min face mask; HNC 10 = humidified high-flow nasal cannula 10 L/min; HNC 30 = humidified high-flow nasal cannula 30 L/min; HNC 50 = humidified high-flow nasal cannula 50 L/min; NC = 4 L/min nasal cannula; NV 12/5 = noninvasive positive-pressure ventilation 12/5; NV 20/10 = noninvasive positive pressure ventilation 20/10; P1–P10 = participants 1–10; RA = room air.