Dry Powder and Budesonide Inhalation Suspension Deposition Rates in Asthmatic Airway-Obstruction Regions

Table 2

European Standardization Committee gives a definition that particle with 2-6 µm diameter deposits on tracheobronchi.

Deposition region	Particle diameter (µm)
Upper airways	>5
Tracheobronchi	2–6
Alveoli	0.5–3

European 135 standardization committee IEN 44-1 : 2007 (E). Aerosol particles of diameter: >5 µm will deposit in the upper airways; 2–6 µm will deposit in the tracheobronchi; 0.5–3 µm will deposit in the alveoli. These data were corroborated by >1,000 published papers and books.