The temporal variations of the airborne radon decay product dose rate and deposited radon decay product activities, as well as the within-house and house-to-house variations of radon concentrations, were evaluated through repeated field measurements. Long-term average radon and surface-deposited radon decay product concentrations were measured in 76 rooms of 38 houses. Temporal variation of radon, as well as airborne and surface-deposited radon decay products, were measured in 11 of the 38 houses during two different seasons. Environmental factors that have the potential to influence airborne dose rate and deposited radon decay products were also studied. Airborne dose rates were calculated from the unattached and attached potential alpha energy concentrations using two dosimetric models. For one model, the observed dose variations were 103%, 74%, 58%, and 60% for the total, house-to-house, within-house, and within-room temporal variations, respectively. For the other model, the dose variations were 100%, 66%, 61%, and 46%, respectively. Surface-deposited 214Po showed variations of 79%, 57%, 42%, and 48%, respectively. These substantial radon decay product concentration variations suggest that multiple locations and time-integrated measurements are needed to make an accurate assessment of the chronic radon-related doses in homes. Smoking was the environmental factor that had the largest temporal and spatial effect on airborne radon decay product dose rates.
1Eagle River, MI;
2Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA;
3Department of Occupational and Environmental Health, Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA.
The authors declare no conflicts of interest.
For correspondence contact R. William Field, Department of Occupational and Environmental Health, Department of Epidemiology, College of Public Health, S327 CPHB, 145 North Riverside Drive, University of Iowa, Iowa City, IA 52242, or email at firstname.lastname@example.org.
(Manuscript accepted 5 August 2018)