scholarly journals Evaluation of soil-gas transport of organic chemicals into residential buildings: Final report

1988 ◽  
Author(s):  
A.T. Hodgson ◽  
K. Garbesi ◽  
R.G. Sextro ◽  
J.M. Daisey
Keyword(s):  
Gas Transport ◽  
Residential Buildings ◽  
Soil Gas ◽  
Final Report ◽  
Organic Chemicals

Mapping indoor radon: individual vs. collective hazard

2021 ◽  
Author(s):  
Eric Petermann ◽  
Peter Bossew
Keyword(s):  
Urban Areas ◽  
Gas Permeability ◽  
Residential Buildings ◽  
Indoor Radon ◽  
Hazard Index ◽  
Air Pollutant ◽  
Soil Gas ◽  
Exceedance Probability ◽  
Hazard Mapping ◽  
Building Stock

<p>Indoor radon is considered as an indoor air pollutant due to its carcinogenic effect. Since the main source of indoor radon is the ground beneath the house, we use geogenic Rn as predictor for indoor Rn hazard mapping. In this contribution, we present a model to link geogenic to indoor Rn.</p><p>In a first step, we build a random forest model that utilizes observational data (n=6,293) of Rn concentration in soil gas and soil gas permeability across Germany in combination with auxiliary data (geology, soil physical and chemical properties, climate) to create spatially continuous map of a geogenic radon hazard index. Then, in a second step, this is geogenic radon hazard index map is linked to indoor radon data (n=44,629) via a logistic regression model for calculating the probabilities that indoor Rn exceeds 300 Bq/m³. The estimated probability was averaged for every municipality by considering only the estimates within the built-up area. Finally, the mean exceedance probability per municipality was coupled with the respective residential building stock for estimating the number of residential buildings with indoor Rn above 300 Bq/m³ for each municipality.</p><p>We found that (1) the municipal-scale maps of 300 Bq/m³ exceedance probability (individual hazard) and affected residential buildings (collective hazard) show contrasting spatial patterns, (2) the estimated number of buildings above 300 Bq/m³ in Germany is 345,000 (1.9 % of all residential buildings), (3) areas where 300 Bq/m³ exceedance is greater than 10 % comprise only 0.8 % of the German building stock but 6.3 % of buildings with indoor Rn exceeding 300 Bq/m³, and (4) most urban areas and most high-radon residential buildings (77 %) are located in low hazard regions.</p><p>The implications for Rn protection are twofold: (1) the Rn priority area concept is cost-efficient in a sense that it allows to find the most buildings that exceed a threshold concentration with a given amount of resources, and (2) for an optimal reduction of lung cancer risk areas outside of Rn priority areas must be addressed since most hazardous indoor Rn concentrations occur in low to medium hazard areas.</p>

scholarly journals Technical Note: Isotopic corrections for the radiocarbon composition of CO<sub>2</sub> in the soil gas environment must account for diffusion and diffusive mixing

2019 ◽  
Vol 16 (16) ◽  
pp. 3197-3205
Author(s):  
Jocelyn E. Egan ◽  
David R. Bowling ◽  
David A. Risk
Keyword(s):  
Gas Transport ◽  
Transport Model ◽  
Stable Carbon Isotope ◽  
Technical Note ◽  
Soil Gas ◽  
Soil Production ◽  
Gas Environment ◽  
Diffusive Mixing ◽  
Mass Dependent ◽  
Mass Dependent Fractionation

Abstract. Earth system scientists working with radiocarbon in organic samples use a stable carbon isotope (δ13C) correction to account for mass-dependent fractionation, but it has not been evaluated for the soil gas environment, wherein both diffusive gas transport and diffusive mixing are important. Using theory and an analytical soil gas transport model, we demonstrate that the conventional correction is inappropriate for interpreting the radioisotopic composition of CO2 from biological production because it does not account for important gas transport mechanisms. Based on theory used to interpret δ13C of soil production from soil CO2, we propose a new solution for radiocarbon applications in the soil gas environment that fully accounts for both mass-dependent diffusion and mass-independent diffusive mixing.

Characterizing the impact of diffusive and advective soil gas transport on the measurement and interpretation of the isotopic signal of soil respiration

2010 ◽  
Vol 42 (3) ◽  
pp. 435-444 ◽  
Author(s):  
Zachary E. Kayler ◽  
Elizabeth W. Sulzman ◽  
William D. Rugh ◽  
Alan C. Mix ◽  
Barbara J. Bond
Keyword(s):  
Soil Respiration ◽  
Gas Transport ◽  
Soil Gas ◽  
The Impact ◽  
Isotopic Signal

Development of an in-situ CO­2 gradient sampler

2020 ◽  
Author(s):  
Laurin Osterholt ◽  
Martin Maier
Keyword(s):  
Gradient Method ◽  
Gas Transport ◽  
Soil Gas ◽  
Diffusivity Coefficient ◽  
Tracer Gas ◽  
3D Print ◽  
Gas Diffusivity ◽  
Gas Fluxes ◽  
Set Up

&lt;p&gt;Gas fluxes between soil and atmosphere play an important role for the global greenhouse gas budgets. Several methods are available to determine soil gas fluxes. Besides the commonly used chamber methods the gradient method becomes more and more important. Chamber methods have the disadvantage that the microclimate can be influenced by the chamber which can affect gas fluxes. This problem does not occur with the gradient method. Furthermore the gradient method has the advantage that it can provide information about the depth profile of gas production and consumption in the soil.&lt;/p&gt;&lt;p&gt;The concept of the gradient method is to calculate gas fluxes by the vertical concentration gradient of a gas in the soil. For the calculation of the flux the effective diffusivity coefficient of the soil is needed. This can be approximated by models or by lab measurements. However, both of these approaches often fail in explaining site specific characteristics and spatial variability. Another way to determine soil gas diffusivity is to apply the gradient method using a tracer gas. By the injection of a tracer gas with known flux soil gas diffusivity can be measured in-situ.&lt;/p&gt;&lt;p&gt;We developed an innovative sampling set-up to apply an improved gradient method including the possibility to determine soil gas diffusivity in situ. We designed a sampler with build-in CO&lt;sub&gt;2&lt;/sub&gt; sensors in multiple depths that can easily be installed into the soil. With this sampler CO&lt;sub&gt;2&lt;/sub&gt; concentrations can be measured continuously in several depths. This enables the identification of short-time effects such as the influence of wind-induced pressure pumping on gas transport. The sampler allows tracer gas injection into the soil for in-situ diffusivity measurement. We decided for CO&lt;sub&gt;2 &lt;/sub&gt;as a tracer gas because it can be measured with small sensors which keep the set-up simple. To account for the natural CO&lt;sub&gt;2&lt;/sub&gt; production in the soil we developed a differential gas profile approach. Using an additional reference sampler allows measuring the natural CO&lt;sub&gt;2&lt;/sub&gt; gradient without the tracer signal, and thus subtracting the tracer CO&lt;sub&gt;2&lt;/sub&gt; signal from the natural CO&lt;sub&gt;2&lt;/sub&gt; signal.&lt;/p&gt;&lt;p&gt;The sampler consists of one 3D print segment per depth each containing one CO&lt;sub&gt;2&lt;/sub&gt; sensor. These parts can be combined to a sampler with flexible amount of measurement depths. The construction with individual segments allows a better maintenance in case of sensor defects. For the installation of the sampler a hole has to be drilled, into which the sampler is inserted. To prevent gas bypassing along the wall of the drill hole we equipped each segment with an inflatable gasket between the measurement locations.&lt;/p&gt;&lt;p&gt;In a next step we will evaluate the sampler and test it in the lab and under different environmental conditions. We expect that with this sampler we will be able to run gas transport experiments in the field with a high temporal resolution and relatively low effort.&lt;/p&gt;&lt;p&gt;&lt;em&gt;Acknowledgements&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;We thank Alfred Baer and Sven Kolbe for the technical support.&lt;/em&gt;&lt;/p&gt;

Poly-Use Multi-Level Sampling System for Soil-Gas Transport Analysis in the Vadose Zone

2013 ◽  
Vol 47 (19) ◽  
pp. 11122-11130 ◽  
Author(s):  
Philipp A. Nauer ◽  
Eleonora Chiri ◽  
Martin H. Schroth
Keyword(s):  
Vadose Zone ◽  
Gas Transport ◽  
Soil Gas ◽  
Sampling System ◽  
Transport Analysis ◽  
Multi Level

220Rn/222Rn Isotope Pair as a Natural Proxy for Soil Gas Transport

2013 ◽  
Vol 47 (24) ◽  
pp. 14044-14050 ◽  
Author(s):  
Stephan Huxol ◽  
Matthias S. Brennwald ◽  
Ruth Henneberger ◽  
Rolf Kipfer
Keyword(s):  
Gas Transport ◽  
Soil Gas
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