Radon concentrations and infiltration rates measured in conventional and energy-efficient houses

To elucidate any connection between high radon concentrations and low-infiltration houses, we have concurrently measured the 222Rn concentration and the infiltration rate in U.S. houses. Three housing surveys have been undertaken: one in "energy-efficient" houses located throughout the U.S. and two in "conventional" houses in the San Francisco area and in Maryland. In each of the groups surveyed, no clear correlation was observed between 222Rn concentrations and infiltration rate, although each parameter varied over a wide range. Infiltration rates for the entire sample, numbering 98 houses, ranged between 0.02 and 1.6 air changes per hr, and 222Rn concentrations ranged from 0.1 to 27 pCi/l. It appears that the major cause of the observed differences in 222Rn concentration is variation from one house to another in the rate at which 222Rn enters houses from its sources.