Become an
Expert in Spirometry

Inhaled particle size and deposition

Question 6b

Assume that the flow at the level of the trachea is 500 milliliter per second, and that tracheal diameter is 2 cm.

What is the gas speed in the trachea?


The surface area, according to the graph, is about 12 cm², the volume flow is 500 cm³ per second. Hence the velocity is 500/12, or about 40 cm/s. This is about 1/4 times the velocity at the level of the trachea.

Top of page | | | ©Philip H. Quanjer