Exhalation of radon-222 from building materials

Reports some results of field measurements of radon levels in apartments and houses and shows that summer measurements with high natural ventilation rates are generally lower than winter measurements. Suggests exhalation of radon from building materials can be studied by placing samples of material in closed vessels and following the growth of activity in the vessels. Shows that a ventilation rate of one air change per hour will lower the theoretical maximum level to 0.008 of the unventilated maximum value.