Table 1

(A) Fraction of particles escaping the headbox relative to open frame (no headbox) measurements, and 95% CI at 10, 20, 30, 40 and 50 L/min of HFNO and (B) estimated fraction of particles escaping the box calculated using a computational fluid dynamic model and the estimated effect of cough

 (A) Measured experimental data (to four decimal places) Flow rate Open headbox Headbox+Blanket Headbox+Filter Mean CI (95%±) Mean CI (95%±) Mean CI (95%±) 10 0.1757 0.0224 0.4321 0.0596 0.0002 6.54E-06 20 0.1552 0.0198 0.7571 0.1044 0.0002 6.54E-06 30 0.2991 0.0382 0.6894 0.0951 0.0002 6.54E-06 40 0.6015 0.0768 0.5779 0.0797 0.0002 6.54E-06 50 0.5774 0.0737 0.6051 0.0834 0.0003 9.81E-06 Mean 0.3618 0.0462 0.6123 0.0844 0.0002 7.20E-06 (B) Computer simulated data and effect of cough (to three decimal places) Open headbox Headbox+Blanket Headbox+Filter Computer simulation data (average of 10 and 50 L/min) 0.451 0.211 0.017 Experimental data (average of 10 and 50 L/min) 0.376 0.519 0 Error between experiment and simulation 0.075 −0.308 0.017 Simulated cough 0.469 0.15 0.01