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Time-averaged exposures to sup 220 Rn and sup 222 Rn progeny in Colorado homes

Journal Article · · Health Physics; (USA)
; ;  [1]
  1. Department of Energy, Grand Junction Projects Office, CO (USA)

Week-long time-averaged exposures to naturally occurring {sup 220}Rn and {sup 222}Rn progeny have been measured at several locations in Colorado by monitoring the alpha activity collected continuously on a fixed-membrane filter. The alpha-energy spectrum associated with the activity collected on the filter was recorded every 15 min using a microcomputer-controlled alpha spectrometer. The alpha counts observed in three energy regions permitted complete separation of the contributions from each decay chain, and calculation of the separate time-averaged potential alpha-energy concentrations in air from {sup 220}Rn progeny, PAEC(Tn), and from {sup 222}Rn progeny, PAEC(Rn). The time-averaged PAEC(Tn) ranged from 0.3 to 6.9 mWL at 12 indoor locations, and the time-averaged PAEC(Rn) ranged from 1.0 to 59.0 mWL. The ratios of the indoor PAEC(Tn) to indoor PAEC(Rn) ranged from 0.09 to 0.58, with an overall average ratio of 0.32 and a standard deviation of 0.15. The 10 L min-1 flow rate through the filter was selected to approximate the air intake rate of a resting human; the time-averaged PAEC thus represents the progeny concentrations that would have been inhaled by a person breathing the same atmosphere.

OSTI ID:
6711435
Journal Information:
Health Physics; (USA), Journal Name: Health Physics; (USA) Vol. 58:6; ISSN 0017-9078; ISSN HLTPA
Country of Publication:
United States
Language:
English