Occupational Intakes of Radionuclides Part 1 - ICRP
Occupational Intakes of Radionuclides Part 1 - ICRP
Occupational Intakes of Radionuclides Part 1 - ICRP
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DRAFT REPORT FOR CONSULTATION<br />
Figure 3. Respiratory tract regions defined in the Human Respiratory Tract Model (HRTM).<br />
Note that the oral part <strong>of</strong> the pharynx is no longer part <strong>of</strong> ET2.<br />
3.2.1 Deposition<br />
Aerosols <strong>of</strong> (solid or liquid) particulate materials<br />
(93) The deposition model described in Publication 66 (<strong>ICRP</strong>, 1994a) evaluates<br />
fractional deposition <strong>of</strong> an aerosol in each region, for all aerosol sizes <strong>of</strong> practical<br />
interest (0.6 nm – 100 μm). For the ET regions, measured deposition efficiencies were<br />
related to characteristic parameters <strong>of</strong> particle size and airflow, and were scaled by<br />
anatomical dimensions to predict deposition under other conditions (e.g. sex, ethnic<br />
group). For the thoracic airways, a theoretical model <strong>of</strong> gas transport and particle<br />
deposition was used to calculate particle deposition in each <strong>of</strong> the BB, bb, and AI<br />
regions, and to quantify the effects <strong>of</strong> the subject’s lung size and breathing rate. To<br />
model particle deposition, the regions were treated as a series <strong>of</strong> filters, during both<br />
inhalation and exhalation. The efficiency <strong>of</strong> each was evaluated by considering<br />
aerodynamic (gravitational settling, inertial impaction) and thermodynamic<br />
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