Fig. 3.

Deposition and penetration of BSP and CSP by particle size in the upper airways: (A) Deposition and (B) penetration efficiencies; (C) Deposition and (D) penetrations fractions. The deposition efficiency, $D{E}_i=\frac{\text{mass}\hspace{0.17em}\text{of}\hspace{0.17em}\text{deposited}\hspace{0.17em}\text{particles}\hspace{0.17em}\text{of}\hspace{0.17em}\text{size}\hspace{0.17em}i}{\text{mass}\hspace{0.17em}\text{of}\hspace{0.17em}\text{inhaled}\hspace{0.17em}\text{particles}\hspace{0.17em}\text{of}\hspace{0.17em}\text{size}\hspace{0.17em}i}$, represents the fraction of inhaled particles of a given size i that deposit in the upper airways. Similarly, the penetration efficiency is the fraction of inhaled particles of a given size that penetrate beyond G6. The deposition fraction, $D{F}_i=\frac{\text{mass}\hspace{0.17em}\text{of}\hspace{0.17em}\text{deposited}\hspace{0.17em}\text{particles}\hspace{0.17em}\text{of}\hspace{0.17em}\text{size}\hspace{0.17em}i}{\text{total}\hspace{0.17em}\text{mass}\hspace{0.17em}\text{of}\hspace{0.17em}\text{inhaled}\hspace{0.17em}\text{particles}}$, is defined as the fraction of total inhaled mass that deposits in the upper airways at a given particle size i, and the penetration fraction is the fraction of total inhaled mass penetrating beyond G6 at a given particle size.