Dosimetry of radon and thoron exposures: Implications for risks from indoor exposure
- Pacific Northwest Lab., Richland, WA (United States)
Current estimates of lung-cancer risks due to the inhalation of radon and its progeny in homes are based on extrapolations of excess mortality observed in populations of underground miners. To project lung-cancer risk to the general public it is necessary to account for any effects that different exposure conditions may have on doses received by critical target cells in the respiratory tract. This paper summarizes the results of a review of aerosol parameters, physiological and biological factors, and cells at risk that are involved in comparing doses between mine and indoor environments. The dose received by sensitive cells in the bronchi from exposure to a given amount of potential alpha-energy (commonly given the unit Working Level Month, WLM) is found to be approximately 20% lower indoors that for healthy underground miners. However, this estimate of the ratio of dose per unit exposure in homes compared to that in mines (termed the {open_quotes}K-factor{close_quotes}) is sensitive to the assumed hygroscopic properties of radon-progeny aerosols. The estimate of K varies from about 0.9, if radon-progeny aerosol particles are assumed not to grow hygroscopically in the respiratory tract, to about 0.6 if the ambient particles are assumed to double in size by hygroscopic growth.
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 45158
- Report Number(s):
- CONF-901010--Pt.1
- Country of Publication:
- United States
- Language:
- English
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