ESTIMATING PAST EXPOSURE TO INDOOR RADON FROM HOUSEHOLD GLASS

CR-39 plastic was attached to household glass objects to learn whether residual radioactivity from radon decay products could be measured an d correlated with cumulative radon exposures over defined time periods . Such an approach could be used to increase the completeness of expos ure data collected in epidemiologic studies of residential radon. Inab ility to estimate radon concentrations for all residences adversely ef fects statistical power and thus the ability to detect an effect of ra don exposure on lung cancer risk. A feasibility study was performed to determine if affixing CR-39 surface monitors to selected glass, ceram ic, or enameled objects provided comparable estimates of past resident ial radon exposure to those obtained from year-long ambient alpha trac k-etch measurements. The CR-39 measurements of alpha activity in the s urface of selected objects correlated with ambient radon measurements (R2 = 0.48) provided that reliable information was obtained on the his tory and age of the objects. This technique has now been incorporated into an epidemiologic study of radon and lung cancer to more fully est imate past exposure to indoor radon.