Total deposition fraction versus particle diameter (aerodynamic). — is the NPM criterion; ···· is deposition in all regions of the respiratory tract as defined by the ICRP.(19) All other symbols are deposition fraction in the normal lung at FRC=3000 mL for controlled breathing patterns. Open symbols are data from Heyder et al. (1986): □ is Vt = 500 mL, Q = 250 mL/s; △ is Vt = 1000 mL, Q = 250 mL/s; ○ is Vt = 1000 mL, Q = 500 mL/s. Closed symbols are data of Kim and Hu (1998) and Kim and Jaques (2000): □ is Vt = 500 mL, Q = 250 mL/s; ▲ is Vt = 1000 mL, Q = 250 mL/s; ● is Vt = 1000 mL, Q = 500 mL/s. Vt = tidal breathing volume and Q = air flow rate.