Table 2. Task Group Lung Model Parameter Values (a) Fraction of Inhaled Particles Deposited in the Respiratory System Versus Particle Diameter (b) Particle zd e AMAD Micrometers Fraction of Inhaled Quantity Retained Nasopharyngeal Tracheobronchial Pulmonary Region, D3 Region, dD, Region, D, 0.05 0.1 0.3 0.5 1.0 2.0 5.0 0.001 0.008 0.063 0.13 0.29 0.50 0.77 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.59 0.50 0. 36 0.31 0.23 0.17 0.11 Clearance Parameter Values (4) Translocation Class Ce) W Y D Compartment k te) £, (2) 7 NP a b 0.01 0.01 0.50 0.50 0.01 0.40 TB c d 0.01 0.20 0.95 0.05 0.01 0.20 P e 0.50 0.80 50 g h nea. 0.50 i k n.a. n.a. 0.50 f£ k 7 f£ 0.10 0.90 0.01 0.40 0.01 0.99 0.50 0.50 0.01 0.20 0.01 0.99 0.15 500 0.05 0.40 0.15 k k n. a. 0.20 1 50 50 0.40 1 0. 40 0.05 500 500 1.00 50 1.00 1000 0.40 0.90 (c) Source: U.S. Nuclear Regulatory Commission (1976). Estimated from data of Task Group on Lung Dynamics (Morrow, AMAD is activity mean aerodynamic diameter. (e) DW.Y. = Days, Weeks, Years. (a) (b) (d) (f) (g) k 1966). As amended by ICRP Publication 19 (1972). Ty = Biological Half-Time (days) for pathway k (see Figure 3). fi = Fraction cleared by pathway k (see Figure 3). 521 Cc L f k