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
Flow rate	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