Regional Deposition of Unattached Radon Progeny (Polonium-218) in Tracheobronchial Region

Details

• Personal Author:
  Cohen B ; Li W ; Xiong J
• Description:
  Indoor radon is one of the leading causes of lung cancer. The unattached fraction of radon daughters that reached the tracheobronchial region of human airway deposits efficiently in tracheobronchial region because of its high diffusion coefficient. The aim of this study is to investigate the deposition of unattached Po-218 in tracheobronchial region and compare with the existing theories. To measure the regional deposition of Po-218, a method that used iodine vapor as a surrogate of Po-218 has been developed. The experiments were conducted in a tracheobronchial replicate cast whose inner surface was coated with Na OH impregnated charcoal powder. This coating can trap iodine molecules by converting iodine into iodide and idodate so that the iodine gas molecules, behaving like particles, stick to a surface upon contact. It has been shown experimentally that the efficiency of this coating is close to 100%. The deposition of iodine in the cast is determined by measuring the iodine concentration before and after the cast. The experiment has been conducted in the flow rate range of 5-50 LPM. It is found that the deposition of iodine can be described by diffusion in laminar flow. This result is different from that observed in previous experiment with submicrometer size particles (40-200 nm) which showed that the deposition is between the estimate for diffusion in laminar flow and the estimate for the diffusion in plugflow. Further study has shown that this discrepancy is caused by the difference in flow pattern through larynz (sinusoidal for the particle study vs. constant flow for the iodine study) and the effect of charge on particles. The result of this study will be useful in modeling not only the radon lung dosimetry but also the deposition of all vapor and nanometer size particles whose lung deposition is dominated by diffusion. [Description provided by NIOSH]
• Subjects:
  Lung Occupational Health Radiation Dosimeters Respiratory System Safety Solvents
• Keywords:
  Dosimetry Humans Inhalation Lung Tissue Models Nanoparticles Radon Radon Daughters Vapors
• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  District of Columbia ; New York ; OSHA Region 2 ; OSHA Region 3
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  49
• NIOSHTIC Number:
  nn:20060167
• Citation:
  American Industrial Hygiene Conference and Exposition, May 20-24, 1996, Washington, D.C. Fairfax, VA: American Industrial Hygiene Association, 1996 May; :49
• CAS Registry Number:
  Polonium (CAS RN 7440-08-6) ; Radon (CAS RN 10043-92-2)
• Federal Fiscal Year:
  1996
• Performing Organization:
  Mount Sinai School of Medicine, New York
• Peer Reviewed:
  False
• Start Date:
  19920701
• Source Full Name:
  American Industrial Hygiene Conference and Exposition, May 20-24, 1996, Washington, D.C.
• End Date:
  19970630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:419dc8d744c756a1c9b3951b038842f5bd602431a23500293a36cf27db6fcf6e00114561d413c89ff65f9da4736252ee1adb7ed58eb81a6b8a0767268c452d97
• Download URL:
  https://stacks.cdc.gov/view/cdc/224161/cdc_224161_DS1.pdf
• File Type:
  [PDF - 1.41 MB ]