To provide detailed information for bronchial dose estimates, aerosol particle size distributions, and radon gas concentration, measurements were made in six residential homes and three laboratory rooms in different office buildings in the city of Ottawa. In the literature, most particle size distribution measurements are taken with samplers operating for a few days at most. In this study, the particle size samplers collected the samples from 77 to 162 d. The equilibrium factor determined from the long-term measurements ranged from 0.6 to almost 1 with an average of 0.75. Even though radon concentrations were quite different between residential setting and office buildings, the average equilibrium factor was similar in the two different indoor environments. The results suggest that at least in some basements, if they were occupied, the radon dose would be about twice as high as normally estimated from the conventional Feq value of 0.4.
*New York University School of Medicine, 550 First Avenue, New York, NY 10016; †Radiation Protection Bureau, Health Canada, 2720 Riverside Drive, Ottawa K1A 0K9, Canada; ‡Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
The authors declare no conflict of interest.
For correspondence contact: Jing Chen, Radiation Protection Bureau, Health Canada, 2720 Riverside Drive, Ottawa K1A 0K9, Canada, or email at firstname.lastname@example.org.
(Manuscript accepted 4 October 2011)