Al. Robinson et al., SOIL-GAS ENTRY INTO HOUSES DRIVEN BY ATMOSPHERIC-PRESSURE FLUCTUATIONS - THE INFLUENCE OF SOIL PROPERTIES, Atmospheric environment, 31(10), 1997, pp. 1487-1495
Atmospheric pressure fluctuations can draw soil gas into houses withou
t the indoor-outdoor pressure differences commonly associated with the
advective entry of radon and other soil-gas contaminants. To study th
is phenomenon, we employ a transient finite-element model based on Dar
cy's law to simulate the soil-gas flow around a prototypical basement
caused by changes in atmospheric pressure. The characteristic response
time and the capacitance of the soil are used to characterize how cha
nges in permeability, air-filled porosity, and water-table depth affec
t this soil-gas how. The shorter the characteristic response time and
the larger the capacitance of the soil, the larger the soil-gas flow r
ate into a basement caused by a given fluctuation in atmospheric press
ure. Such a soil must have a high permeability and a large air-filled
porosity. The addition of a high permeability subslab gravel layer inc
reases the soil-gas how rate into the basement by a factor of similar
to 3. Relative to entry driven by steady indoor-outdoor pressure diffe
rences, contaminant entry induced by atmospheric pressure fluctuations
will likely be most important in houses situated in a soil of low per
meability (<10(-12) m(2)) and large air-filled porosity. (C) 1997 Else
vier Science Ltd.