Combined stack effect in houses and eskers explaining transients in radon source.

Concentrations of radon indoors and temperatures indoors and outdoors have been recorded every hour with some interruptions for one 12-week period in a dwelling situated on top of an esker outside Stockholm. The concentration of radon in the house shows variations, which can be explained as a combined stack effect in the esker and in the building. The stack effect is not only dependent on temperature differences, but also on the pressure effect that the wind creates. In this study no local wind observations have been made as this was not the main purpose on this occasion. The temperature in the esker is assumed to be at a constant level equivalent to groundwater temperature. From these data the pressure gradient has been calculated and then compared with the radon source.