Table 2 Multivariate Prediction Models.

From: Radon exposure is rising steadily within the modern North American residential environment, and is increasingly uniform across seasons

# homes > level in modelRadon > 100 Bq/m3Radon > 200 Bq/m3Radon > 500 Bq/m3
165942657
Decade of ConstructionORL95% CIU95% CIORL95% CIU95% CIORL95% CIU95% CI
Pre 19601.00Reference 1.00Reference 1.00Reference 
1960–19801.741.292.351.670.962.880.470.073.39
1980–20001.581.192.091.570.932.651.650.377.46
Post 20003.072.314.082.681.614.473.340.7714.41
Basement Ft2
<7501.00Reference 1.00Reference 1.00Reference 
750- < 17501.010.851.211.100.851.431.150.562.37
1750- < 35001.060.841.331.140.821.591.640.723.71
≥35001.050.691.591.580.932.682.770.918.45
Building type category
Semi-detached1.00Reference       
Detached2.131.652.74      
Other0.380.081.78      
Walkout basement
No1.00Reference 1.00Reference 1.00Reference 
Yes0.770.650.930.620.470.820.600.291.22
Upstairs Window Use
Rarely1.00Reference 1.00Reference 1.00Reference 
Sometimes1.010.861.191.000.801.260.600.331.07
Frequently (warm)0.720.570.920.590.390.900.670.251.81
Frequently (always)0.570.440.720.630.420.940.540.181.58
Basement Ceiling Height
8 ft of less1.00Reference 1.00Reference 1.00Reference 
9 ft1.261.041.541.541.192.001.831.013.32
10 ft or greater1.380.872.201.821.043.180.650.094.96
Furnace/Heat Type
Natural gas1.00Reference      
Propane or Oil0.290.061.50      
Wood1.070.711.60      
Electric0.930.641.36