EMANATION OF RADON FROM HOUSEHOLD GRANITE

Abstract

Emanation of radon (²²²Rn) from granite used for countertops and mantels was measured with continuous and integrating radon monitors. Each of the 24 granite samples emitted a measurable amount of radon. Of the two analytical methods that utilized electret-based detectors, one measured the flux of radon from the granite surfaces, and the other one measured radon levels in a glass jar containing granite cores. Additional methods that were applied utilized alpha-scintillation cells and a continuous radon monitor. Measured radon flux from the granites ranged from 2 to 310 mBq m⁻² s⁻¹, with most granites emitting <20 mBq m⁻² s⁻¹. Emanation of radon from granites encapsulated in airtight containers produced equilibrium concentrations ranging from <0.01 to 11 Bq kg⁻¹ when alpha-scintillation cells were used, and from <0.01 to 4.0 Bq kg⁻¹ when the continuous radon monitor was used.