Lung cancer rate vs. mean radon level in U.S. counties of various characteristics.

Plots of lung cancer rates corrected for smoking prevalence vs. average home radon levels are presented for U.S. counties with a wide variety of socioeconomic characteristics. The data are generally well described by the same negative slope linear, plus positive slope quadratic, "standard" curve. Plots are presented for geographic regions and these are also reasonably well fit by the standard curve. The findings are not consistent with predictions based on a linear no-threshold model.