Deposition of charged particles on lung airways.
The effect of a single electric charge on the efficiency with which ultrafine particles deposit in human airways has been investigated. When inhaled short-lived radon progeny are attached to electrically neutral particles their deposition efficiency is controlled by diffusion. But most ambient particles carry one, or a few, charges. We measured and compared the deposition (DE) of singly charged, charge-neutralized, and zero-charge 20-nm and 125-nm particles in hollow-cast models of human airways. These particle sizes were selected because they are about where modal peaks occur for the activity of the short-lived radon progeny in indoor air. For singly charged 20-nm particles deposition (+/- standard error) in the casts was 3.4 +/- 0.3 times that for charge neutralized aerosols and 5.3 +/- 0.3 times the amount deposited for zero-charged particles. Corresponding ratios for the 125-nm particles were 2.3 +/- 0.3 and 6.2 +/- 0.7. Since most ambient particles are charged this effect must be considered when models are used to predict dose from inhaled ultrafine particles.
Cohen
B S
BS
Nelson Institute of Environmental Medicine, New York University Medical Center, Tuxedo 10987, USA.
Xiong
J Q
JQ
Fang
C P
CP
Li
W
W
D000328:Adult; D000336:Aerosols; D006801:Humans; D007477:Ions; D008168:Lung / Q000378:metabolism*; D008297:Male; D008961:Models, Structural; D010969:Plastics; D012137:Respiratory System / Q000378:metabolism*; D013499:Surface Properties; D014132:Trachea
D000336:Aerosols; D007477:Ions; D010969:Plastics