Radon concentrates and ventilation rates in Eastern Pennsylvania houses.

A representative panel of 37 conventional houses in Eastern Pennsylvania was chosen. Each house was located with respect to its geological formation (the underlying substrate). Blower-door ventilation measurements were made. The concentration of radon in the domestic water supplies was analysed and passive radon monitors were used to measure the radon in the air. It was concluded that the radon in these houses arises largely from the soil and passes through the foundations. Newer houses were found to have more radon, experience lower ventilation rates and show less ventilation variability from house to house than older houses.