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On the potential importance of transient air flow in advective radon entry into buildings
Author(s) -
Narasimhan T. N.,
Tsang Y. W.,
Holman H. Y.
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i006p00821
Subject(s) - advection , radon , atmospheric pressure , permeability (electromagnetism) , air permeability specific surface , transient (computer programming) , soil science , environmental science , atmospheric sciences , pressure gradient , geology , mechanics , airflow , homogeneous , moisture , meteorology , materials science , physics , chemistry , thermodynamics , computer science , operating system , biochemistry , oceanography , layer (electronics) , quantum mechanics , membrane , composite material
We have investigated, using a mathematical model, the temporal variations of air flux within the soil mass surrounding a basement in the presence of time dependent periodic variations of barometric pressure and a persistent under‐pressure at the basement. Our results of transient air flow show that for a homogeneous soil medium, the effects of barometric fluctuations are most significant in the cases where soil permeability to air is low and the fluctuation frequency is high. In these cases, the barometric fluctuation can greatly enhance the magnitude of fluxes as well as introduce flow direction reversals from surrounding soil into the basement. These large fluxes with direction reversals have strong implications in regard to advective transport of radon. Our results suggest that the transient oscillations have to be accounted for in quantifying radon entry into buildings. In the actual field set up, the transient behavior will be further influenced by soil permeability heterogeneity, by soil moisture variations, and by the effects of multiple periodic components in the barometric pressure fluctuations.