Measurement of the indoor and outdoor (220)Rn (thoron) equilibrium factor: application to lung dose

Radiat Prot Dosimetry. 2010 Oct;141(4):357-62. doi: 10.1093/rpd/ncq228. Epub 2010 Sep 10.

Abstract

A miniature four-chamber alpha track detector was developed that measures both (222)Rn (radon) and (220)Rn (thoron), in duplicate. Using this detector and the previous long-term measurements of the (220)Rn decay products (212)Pb, and (212)Bi, an equilibrium factor, F(eq), is derived for both outdoor and indoor (220)Rn environments (0.004±0.001 outdoors and 0.04±0.01 indoors). The lung airway dose can then be calculated from a dose factor from UNSCEAR that requires the equilibrium equivalent thoron concentration (EEC), i.e. the product of F(eq) and the (220)Rn gas concentration. The lung dose from thoron in domestic or occupational surveys is often overlooked. The values of F(eq) for thoron in several published studies are in general agreement with the values reported here. Thus, a long-term alpha track measurement of thoron multiplied by an appropriate indoor or outdoor equilibrium factor yields the EEC, which can be used to assess bronchial lung dose.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Air Pollutants, Radioactive
  • Air Pollution / analysis*
  • Air Pollution, Indoor / analysis*
  • Calibration
  • Environmental Exposure
  • Humans
  • Lung / radiation effects
  • Radiation Monitoring
  • Radiometry
  • Radon / analysis*
  • Radon Daughters / analysis*
  • Risk
  • United States

Substances

  • Air Pollutants, Radioactive
  • Radon Daughters
  • Radon