Descriptive statistics for particles measured in the breathing-zone of the test subject (30 cm from mouth)
| Event | Mean | Min | Max | Median | 0.25 | 0.75 | Dispersion % |
| Particle size ≤1.0 µm | |||||||
| LFNC | 73.0 | 21.2 | 151.0 | 60.9 | 41.5 | 106.5 | 107 |
| LFNC+cough | 222.7 | 44.9 | 1167.4 | 122.9 | 71.0 | 248.4 | 144 |
| HFNC | 101.2 | 15.9 | 317.1 | 67.8 | 38.5 | 130.0 | 135 |
| HFNC+cough | 190.9 | 36.4 | 1444.7 | 91.9 | 61.8 | 167.6 | 115 |
| HFNC+M | 89.3 | 25.3 | 230.5 | 54.8 | 41.0 | 137.2 | 176 |
| HFNC+M+cough | 103.1 | 29.2 | 270.5 | 96.7 | 48.2 | 156.5 | 112 |
| NIV | 77.7 | 20.6 | 245.9 | 66.4 | 33.3 | 102.4 | 104 |
| NIV+cough | 90.2 | 28.0 | 263.5 | 73.8 | 39.2 | 112.2 | 99 |
| Particle size >1 µm and ≤5 µm | |||||||
| LFNC | 22.1 | 7.3 | 70.2 | 18.6 | 14.8 | 24.0 | 49 |
| LFNC+cough | 47.3 | 13.7 | 242.0 | 29.3 | 17.7 | 40.4 | 77 |
| HFNC | 42.4 | 1.8 | 236.7 | 25.7 | 14.9 | 46.0 | 121 |
| HFNC+cough | 41.8 | 13.3 | 186.4 | 25.0 | 21.4 | 37.7 | 65 |
| HFNC+M | 33.5 | 7.6 | 110.2 | 22.4 | 15.4 | 39.4 | 107 |
| HFNC+M+cough | 27.3 | 8.4 | 80.1 | 23.4 | 17.3 | 29.1 | 50 |
| NIV | 21.6 | 5.1 | 51.8 | 22.1 | 13.3 | 26.4 | 59 |
| NIV+cough | 24.7 | 6.0 | 72.7 | 21.6 | 16.3 | 31.2 | 69 |
| Particle size >5 µm | |||||||
| LFNC | 1.7 | 0.5 | 5.5 | 1.2 | 0.9 | 2.1 | 100 |
| LFNC+cough | 1.7 | 0.3 | 5.5 | 1.4 | 1.0 | 1.8 | 57 |
| HFNC | 3.6 | 0.1 | 22.8 | 1.9 | 1.2 | 3.5 | 122 |
| HFNC+cough | 3.1 | 0.6 | 24.6 | 1.6 | 1.1 | 2.9 | 113 |
| HFNC+M | 3.7 | 0.4 | 20.5 | 1.7 | 1.1 | 3.9 | 167 |
| HFNC+M+cough | 2.6 | 0.8 | 9.8 | 1.9 | 1.2 | 2.9 | 88 |
| NIV | 1.3 | 0.3 | 2.5 | 1.3 | 0.9 | 1.8 | 65 |
| NIV+cough | 1.8 | 0.5 | 4.5 | 1.5 | 1.0 | 2.2 | 79 |
Descriptive statistics for the particle concentration (three particle size groups) measured by the breathing-zone single sensor (APS 3321) during all events. The unit used is the mean particle concentration in number per litre during the event. The dispersion of the distribution is presented as the per cent-wise ratio between the interquartile range and the median. The statistical distributions of particle counts were skewed for nearly all events and particle sizes (Shapiro–Wilk test p<0.05). LFNC: low-flow nasal cannula; HFNC: high-flow nasal cannula; NIV: noninvasive positive-pressure ventilation; M: surgical mask.