evidence from experiments that used rat tracheal epithelium. Measurements of activity-weighted particle-size distributions relevant to the conditions experienced by historical cohorts of miners are unlikely to become available, because those conditions no longer occur. However, the committee recommends that a Phase II Research Council committee
Use noninvasive methods for monitoring ventilation to obtain additional information that is relevant to radon dosimetry and an improved model.
Continue to evaluate information on the cells at risk for radon-induced lung cancer.
Use activity-weighted size-distribution data that have become available on residences.
Use the recent data regarding growth of particles from various sources typically found in the home.
Apply the reduced uncertainties in various aspects of lung dosimetry and use revised factors to reassess the uncertainties associated with the lung dosimetry in risk calculations.