Student Research: Gary Hartmann
MS, , 1994
The Contribution of Radon-220 (Thoron) to Indoor Radon Levels in Western Washington
Air filter samples were taken at 23 indoor sites throughout Western Washington and the relative contributions of radon-220 daughters and radon-222 daughters to total activity and to potential alpha energy concentration (PAEC) were determined.
It was found that the ratio of Rn-220 daughter to Rn-222 daughter concentration (in Bq/m3) ranged from 0.007 to 0.282 with a geometric mean of 0.031 (95% CI: 0.004-0.194). The ratio of Rn-220 daughter to Rn-222 daughter PAEC (in nJ/m3) was estimated to range from 0.09 to 3.89 with a geometric mean of 0.46 (95% CI: 0.07-2.93). Based on these data, it was estimated that the inhalation of Rn-220 results in 56 to 85 of the 2500 annual lung cancer deaths in the state of Washington.