The New Jersey Department of Environmental Protection (NJDEP) has announced an update to the Johnson & Ettinger (J&E) Spreadsheets to reflect changes to the NJDEP Vapor Intrusion Guidance of (updated August 2016). These EPA J&E Spreadsheets are used to investigate the migration of volatile chemical vapors beneath overlying buildings. The EPA provides a vapor intrusion investigation calculator on their website provided in the link below.
The J&E Model, developed in 1991, is provided as a supplementary tool for the investigation of volatile contaminants which may impact indoor air in an overlying building. Basic information regarding the building and contaminants themselves are needed for the calculation. In addition, basic soil properties, such as porosity and capillary characteristics are also required. NJDEP’s update considers New Jersey’s Impact to Groundwater Screening Levels for specific contaminants, in addition to updates to chemical and toxicity factors for specific contaminants.
NJDEP recommends collecting a soil core for laboratory analysis for any soil textures other than sand so median USDA soil texture can be determined, as described in the NJDEP Vapor Intrusion Guidance (August 2016). The site-specific, laboratory-determined value can then be used in the calculation. This should not be confused with the standard values for soil properties (soil moisture, bulk density and porosity), as these default values are already built into the calculator and must be used.
This calculator should be used as an additional resource in any vapor intrusion investigation conducted in New Jersey. A proper investigation includes a site-specific assessment of the building on the subject property with a potential vapor concern, and should consist of indoor air and sub-slab soil gas sampling as prescribed in the August 2016 NJDEP Vapor Intrusion Guidance, provided in the link below.