Journal of Applied Physiology, Vol 57, Issue 6 1850-1856, Copyright © 1984 by American Physiological Society
Total deposition of ultrafine sodium chloride particles in human lungs
J. D. Blanchard and K. Willeke
The total deposition of monodisperse, 0.026-0.19 micron (dry volume
equivalent diameter) sodium chloride particles in the lungs of five healthy
subjects, who breathed orally, was measured. For a tidal volume of 1,000 ml
and flow rate of 500 ml/s, the percentages deposited were: 37.2 +/- 8.4%
(mean +/- SD) for 0.026 micron, 23.8 +/- 3.3% for 0.051 micron, 22.8 +/-
3.1% for 0.096 micron, and 31.8 +/- 6.2% for 0.19 micron particles. The
deposition minimum corresponded to a particle size of approximately 0.08
micron. Deposition did not correlate with measures of lung volume or body
size but did correlate with forced expired flow rate after 75% of forced
vital capacity (FVC) exhaled (FEF 75%/FVC) and with percent-predicted
values for FEF 25-75% and FEF 75%. Lengthening the breathing period from 4
to 8 s/breath while maintaining flow rate at 500 ml/s caused an additional
11.3 +/- 3.1% of the inhaled particles to deposit. Sedimentation and
diffusion were found to be the principal deposition mechanisms. These
hygroscopic particles deposited according to sizes they would attain in air
with a relative humidity between 96 and 100%.
