Page 265 - Industrial Ventilation Design Guidebook

226 CHAPTER 5 PHYSIOLOGICAL AND TOXICOLOGICAL CONSIDERATIONS

Hygroscopic Particle Deposition Determined by Initial MMAD
(continuous RH profile, saturated saline, a g~ 1.0}
(Q = 250 mL/min, f~l5 breaths/min)

Hygroscopic Particle Deposition Determined
by Initial Ionic Concentration
(continuous RH profile, MMAD = 2.0 fun)
(Q = 250 mL/min, f = 15 breaths/min)

FIGURE 5.29 Predicted effects of initial hygroscopic particle properties (initial diameter, ionic
concentration) on the airway deposition profile. 102 Larger initial particles are predicted (left) to deposit
in the more proximal airways while fine particles reach pulmonary airways in much greater concentra-
tions. Initially high ionic concentrations (saturated saline) are predicted (right) to deposit primarily in
upper airways, probably due to their rapid growth during transit through the upper airway. More moder-
ate growth rates represented by normal saline aerosol result in greater predicted deposition in the pul-
monary airways. Airway generation -(represents the upper airway while the trachea is given as
generation 0.