Deposition of thoron progeny in human head airways

Journal Article · Sat May 01 00:00:00 EDT 1993 · Aerosol Science and Technology; (United States)

DOI:https://doi.org/10.1080/02786829308959610· OSTI ID:6204739

Cheng, Yungsung; Su, Yinfong; Yeh, Hsuchi ^[1]; Swift, D L ^[2]

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1. Inhalation Toxicology Research Inst., Albuquerque, NM (United States)
2. Johns Hopkins Univ., Baltimore, MD (United States)

Radon and thoron progeny are ultrafine particles in the size range of 1-200 nm, depending on whether or not they are attached to other aerosol particles. The diffusion coefficient of radon progeny is a critical parameter in determining its dynamics while airborne. Depending on their diffusion coefficient and the breathing pattern of the subject, ultrafine particles have been shown to deposit in the nasal or oral airways. Substantial deposition in the head airways reduces the amount of radioactivity that deposits in the tracheobronchial tree. Thus, for accurate dosimetric calculations, it is important to know the deposition fraction of radon progeny in the head airways. Several adult head airway models were used to study the radon progeny deposition in human nasal and oral airways. Radon-220 progeny ([sup 212]Pb) were used in the study. The particle size as measured by a graded screen diffusion battery was between 1.2 and 1.7 nm, indicating that the particles were molecular clusters. Deposition was measured by collecting filter samples before and after the model and gamma counting the [sup 212]Pb. Experiments were performed under the constant flow rates of 4-20 L/min. Deposition efficiencies were between 63% and 85% in the nasal airway and 48% and 78% in the oral airway. Previously reported deposition data in the same airway model for ultrafine particles between 4.6 and 200 nm and the deposition data of radon progeny were used to establish a turbulent deposition equation covering particle sizes from 1 to 200 nm, the entire size range for attached and unattached radon progeny. 23 refs., 10 figs., 6 tabs.

• DOE Contract Number: AC04-76EV01013
• OSTI ID: 6204739
• Journal Information: Aerosol Science and Technology; (United States), Vol. 18:4; ISSN 0278-6826
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPES AND RADIATION SOURCES
54 ENVIRONMENTAL SCIENCES
AEROSOLS
INHALATION
DAUGHTER PRODUCTS
DEPOSITION
DIFFUSION
DOSIMETRY
EXPERIMENTAL DATA
LEAD 212
RADON 220
RESPIRATORY SYSTEM
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COLLOIDS
DATA
DISPERSIONS
EVEN-EVEN NUCLEI
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
INFORMATION
INTAKE
ISOTOPES
LEAD ISOTOPES
NUCLEI
NUMERICAL DATA
RADIOISOTOPES
RADON ISOTOPES
SECONDS LIVING RADIOISOTOPES
SOLS
070500* - Isotope & Radiation Source Technology- Health & Safety- (1990-)
540130 - Environment
Atmospheric- Radioactive Materials Monitoring & Transport- (1990-)