Size Distribution of Exhaled Particles in the Range from 0.01 to 2.0 µm
Journal article, 2010

This study investigates the number size distribution of endogenously produced exhaled particles during tidal breathing and breathing with airway closure. This is the first time that the region below 0.4 µm has been investigated. The particle concentration was generally lower for tidal breathing than for airway closure, although the inter-individual variation was large. During tidal breathing, the size distribution peaks at around 0.07 µm. This peak is still present during the airway closure manoeuvre, but an additional broad and strong peak is found between 0.2 and 0.5 µm. This suggests that different mechanisms govern the generation of particles in the two cases. The particles produced from airway closure may be attributed to formation of film droplets in the distal bronchioles during inhalation. It is speculated that the very small particles are film droplets originating from the alveolar region.

exhaled particles

size distribution

tidal breathing

airway closure


Helene Holmgren

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Evert Ljungström

University of Gothenburg

Ann-Charlotte Almstrand

University of Gothenburg

Björn Bake

University of Gothenburg

Anna-Carin Olin

University of Gothenburg

Journal of Aerosol Science

0021-8502 (ISSN)

Vol. 41 5 439-446

Subject Categories

Medical Laboratory and Measurements Technologies

Other Physics Topics

Public Health, Global Health, Social Medicine and Epidemiology



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