Table 3.

Fractions of ²¹⁸Po, ²¹⁴Pb and ²¹⁴Bi nuclei originally deposited in airway generations 6–15 and cleared up to airway generation 5

Airway gen. no. of the initial deposition (–)	Average airway length (mm)	Average mucus velocity (mm/min)	Clearance time to generation 5 (s)	Fraction of 218Po cleared up to generation 5 (%)		Fraction of 214Pb cleared up to generation 5 (%)	Fraction of 214Bi cleared up to generation 5 (%)
6	9	0.74	730	6.29		89.39	116.23
7	7.6	0.50	1642	–		61.00	112.04
8	6.4	0.33	2806	–		36.68	88.6
9	5.4	0.22	4279	–		19.27	57.43
10	4.6	0.15	6119	–		8.61	30.16
11	3.9	0.10	8459	–		3.11	12.37
12	3.3	0.07	11,288	–		0.91	3.99
13	2.7	0.05	14,528	–		0.22	1.02
14	2.3	0.03	19,128	–		0.03	0.15
15	2	0.02	25,128	–		–	0.01
16	1.65	0.01	35,028	–		–	–