Elsevier

Atmospheric Environment

Volume 33, Issue 14, 16 June 1999, Pages 2157-2168
Atmospheric Environment

Effects of variable wind speed and direction on radon transport from soil into buildings: model development and exploratory results

https://doi.org/10.1016/S1352-2310(98)00374-4Get rights and content

Abstract

We describe a novel modeling technique, based on Duhamel’s theorem, to study the effects of time-varying winds on radon transport in soil near buildings. The technique, implemented in the model RapidSTART, reduces computational times for transient, three-dimensional, wind-induced soil-gas and radon transport by three to four orders of magnitude compared with conventional finite-difference models. To test model performance, we compared its predictions to analytical solutions of one-dimensional soil-column flow, finite-difference simulations of flow around a full-scale house, and measurements of transient soil–gas and radon entry into an experimental basement structure. These comparisons demonstrate that RapidSTART accurately simulates time-dependent radon transport through soil and its entry into buildings. As demonstrated in a previous study, steady winds can significantly affect radon entry. In this paper, we extend the findings of that study by applying RapidSTART to explore the impacts of fluctuating wind speed and direction on radon entry into a prototypical house. In soils with moderate to high permeability, wind fluctuations have a small to moderate effect on the soil-gas radon concentration field and entry rate into the building. Fluctuating wind direction dominates the impact on radon entry rates, while fluctuating wind speed has little effect. For example, in a soil with a permeability of 10-10 m2, diurnal oscillations in wind direction can increase the predicted radon entry rate by up to 30% compared to steady-state predictions.

References (0)

Cited by (45)

  • Model of radon entry and accumulation in multi-flat energy-efficient buildings

    2021, Journal of Environmental Chemical Engineering
    Citation Excerpt :

    Later, with development of the computer science technologies, the more complex multi-dimension models and time-dependent models became perspective numerical methods of modeling radon sources and transport [3,16]. An application of multi-dimensional computational fluid dynamic models provided a better simulation of the spatial distribution of 222Rn, 220Rn and progeny indoor [1,10,16,44,61] and in the soil air [15,39]. In the time dependent models, dynamic conditions of radon entry may be considered by expressing influencing factors as time variable functions [14,16].

  • Development of radon transport model in different types of dwellings to assess indoor activity concentration

    2021, Journal of Environmental Radioactivity
    Citation Excerpt :

    The importance of the present work is being able to carry out evaluations of indoor Radon before making extensive measurements, also to make a possible assessment of areas and/or buildings with significative risk of presenting high levels of Radon. This goal is poorly treated in literature, and only very few works deal partially with it, studying only selected problem connected with the simulation of Radon flux from fractured rocks, specific soils composition, insulation materials (Ajayi et al., 2018; Riley et al., 1999; Savović et al., 2011a, b; Skubacz et al., 2019; Szajerski and Zimny, 2020). There is absence of papers that compare different types of buildings to evaluate a relative Radon risk index depending on the soil type and building materials.

  • Relating wind-induced gas transport in porous media to wind speed and medium characteristics

    2020, Journal of Petroleum Science and Engineering
    Citation Excerpt :

    Average wind speed and wind speed fluctuations near the surface of porous media potentially affect gas transport within the porous medium and consequently the subsurface-to-atmosphere gas exchange (Poulsen and Moldrup, 2006; Mohr et al., 2016; Pourbakhtiar et al., 2017). Wind-induced gas transport in porous media and exchange across the medium surface is important in connection with, for instance, intrusion of Radon, a radioactive gas, into buildings (Riley et al., 1999; Keskikuru et al., 2000; Wang and Ward, 2002), methane emissions from landfills (Poulsen et al., 2001; Poulsen and Moldrup, 2006), release of greenhouse gases from soil (including agricultural soil) to the atmosphere (Takle et al., 2004; Redecker et al., 2015; Goffin et al., 2015), and water evaporation from soil (Acharya and Prihar, 1969; Novak et al., 2000a, 2000b; Haghighi and Or, 2013, 2015a, 2015b; Poulsen et al., 2019). Impact of near-surface wind action on subsurface gas transport has traditionally been regarded as being controlled by rapid near-surface atmospheric pressure fluctuations induced by wind turbulence (Fukuda, 1955; Scotter and Raats, 1968, 1969; Massman and Frank, 2006; Poulsen and Sharma, 2011).

View all citing articles on Scopus
1

Current address: Department of Mechanical Engineering, Carnegie Mellon, Pittsburgh, PA, USA.

View full text