EVALUATING HOUSEHOLD MINERAL PRODUCTS FOR RADON RELEASE POTENTIAL

Many household mineral products emit radon and some of them could become a health hazard. The radon release potential of these mineral products is evaluated in a two connected polyethylene container system. One container is for the measurement and the other one for the control of the physical conditions of the system.

The radon release potential is measured at 20^°C and 40 to 50 percent relative humidity, as encountered indoors of an average household. The radon level inside a closed container grows with time and follows the natural growth curve, At= Ao(1-e^-λt), where λ is the decay constant of ²²²Rn or 0.1813 day^-1, Ao and At are the initial and the final values of radon activities, and t is the elapsed time. The amount of radon added to indoor radon levels is calculated by dividing the amount of radon at equilibrium in this 5 gallon (19,000 ml) container to the air volume of an average house of 16,000 ft³. Radon is released from a mineral particle by the recoil of radon atom when radium atom decayed by emitting an alpha particle at high energy. Solid massive pieces, like granite countertops, release relatively less radon with similar uranium content as compared with porous medium like concrete blocks or concrete. The latter porous medium was not measured directly, but it can be shown that the sands used for mixing could be of high radon release potential.

The porous medium like concrete blocks and concrete used in the construction of the house could make significant contribution to indoor radon levels and needs to be evaluated further for health hazard.