RADON ENTRY INTO BUILDINGS DRIVEN BY ATMOSPHERIC-PRESSURE FLUCTUATIONS

To examine the effects of atmospheric pressure fluctuations on radon e ntry into houses, we report measurements of soil-gas and advective rad on entry made using an experimental basement. Based on these measureme nts, we quantify the contribution of atmospheric pressure fluctuations , steady indoor-outdoor pressure differences, and molecular diffusion to the long-term radon entry rate into the experimental basement. In t he absence of a steady indoor-outdoor pressure difference, atmospheric pressure fluctuations at the study site induce a radon entry rate 1.5 times greater than that due to molecular diffusion. A steady indoor-o utdoor pressure difference reduces the contribution of atmospheric pre ssure fluctuations to the longterm radon entry rate. For sustained ind oor-outdoor pressure differences with a magnitude greater than 1.5 Pa, atmospheric pressure fluctuations have essentially no effect on the t ime-averaged radon entry rate into the experimental structure. The res ults of this study demonstrate that under certain conditions, such as periods during which indoor-outdoor pressure differences are small, at mospheric pressure fluctuations will contribute measurably to the tota l radon entry rate into a building, potentially doubling indoor concen trations. However, in absolute terms, atmospheric pressure fluctuation s drive approximately the same amount of entry as molecular diffusion and,therefore, will probably not cause houses to have long-term, eleva ted indoor radon concentrations.