The scientific consensus is that the unattached fraction of radon progeny poses a much greater health risk than the attached fraction. Development of a commercial device to determine the concentrations of attached and unattached fractions is essential to count decay products and assess health effects accurately. Phase I involves testing and optimization of improved instrumentation to determine concentrations of radon progeny in the air. The device will differentiate between the attached and unattached fractions of radon progeny. Details on the activity size distribution of particles less than 10 nm can be provided by further analysis of the detection material. Based upon preliminary results, the detector is versatile enough to determine the equilibrium factor and the unattached fraction. Detector capabilities will be evaluated in a variety of controlled aerosol environments. A specific evaluation will be done on the binding potential of tobacco smoke over a wide range of aerosol environments. Research suggests that by changing the configuration and detection materials, sensitivity can be altered to vary run times from the short term (3 to 5 days) to the long term (3 to 6 months). The prototypes can be modified to convert them into inexpensive mail-in devices. This accessibility by the general population will in turn provide more accurate estimates of dose versus exposure under a variety of atmospheric conditions. Improved estimates of dose will reduce the uncertainty in current national lung risk projections.Anticipated Results/Potential Commercial Applications as described by the awardee:Upon completion of Phase I, a working level monitor that can measure the contribution from both the attached and unattached fractions will be developed. This device has direct application for testing radon in homes and for monitoring radon worker exposure levels in a wide variety of radon environments. By making the home test detector easily accessible to the general population (inexpensive and mail-in), a large database can be assembled which will provide specific patterns on the demographics and life-styles of those at the greatest health risk from radon.
