Article

Comparison of the Johnson-Ettinger Vapor Intrusion Screening Model Predictions with Full Three-Dimensional Model Results

School of Engineering, Brown University, Providence, Rhode Island 02912, United States.
Environmental Science & Technology (Impact Factor: 5.33). 02/2011; 45(6):2227-35. DOI: 10.1021/es102602s
Source: PubMed

ABSTRACT

The Johnson-Ettinger vapor intrusion model (J-E model) is the most widely used screening tool for evaluating vapor intrusion potential because of its simplicity and convenience of use. Since its introduction about twenty years ago, the J-E model has become a cornerstone in guidance related to the potential for significant vapor intrusion-related exposures. A few papers have been published that claim it is a conservative predictor of exposure, but there has not been a systematic comparison in the open literature of the J-E model predictions with the results of more complete full three-dimensional descriptions of the phenomenon. In this paper, predictions from a three-dimensional model of vapor intrusion, based upon finite element calculations of homogeneous soil scenarios, are directly compared with the results of the J-E model. These results suggest that there are conditions under which the J-E model predictions might be quite reasonable but that there are also others in which the predictions are low as well as high. Some small modifications to the J-E model are also suggested that can bring its predictions into excellent agreement with those of the much more elaborate 3-D models, in some specific cases of homogeneous soils. Finally, both models were compared with actual field data.

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    • "Sensitivity and uncertainty analysis have been conducted for simple 1-D analytical models such as J&E model [4,19–23]. Although analytical models are simple and fast, these models usually contain many simplified assumptions and thus cannot account for some important aspects that significantly affect the vapor intrusion pathway [2] [24]. Advanced 3-D numerical models that consider multispecies transport, reaction and phase partitioning are more accurate and applicable to describe scenarios with complex model domain and boundary conditions [13] [14]. "
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