A Representative Case Study of the Application of Building Prioritization Framework in Vapor Intrusion Investigations at Industrial Sites

摘要

Current vapor intrusion (VI) guidance documents utilize the results of United States Environmental Protection Agency's (USEPA's) 2013 analysis of data collected from residential buildings in development of inclusion distances and attenuation factors. However, USEPA's 2015 Final VI guidance recognizes that industrial buildings behave differently with respect to VI potential (i.e., open work bays and doors, large wall fans, and greater dilution of volatile organic compounds [VOCs]). Under Naval Environmental Sustainability Development to Integration Program (NESDI) Project #476,* the Department of the Navy (Navy) and CH2M assembled a first-of-its-kind VI relational database specifically for industrial buildings. This database compiled indoor air, subslab soil gas and/or groundwater data for 150 sampling zones in 49 industrial buildings at 12 different installations where chlorinated VOCs impacts were identified. The data were used to quantitatively evaluate how variations in building construction, subsurface characteristics, and source strength impact the potential for VI at industrial buildings. Using the results of the evaluation, the team developed a quantitative ranking system that facilitates prioritizing VI potential at industrial buildings based on how they are influenced by site and building characteristics. This prioritization ranking allows for a phased investigation approach focusing on buildings with the highest VI potential, significantly reducing investigation costs by focusing resources on buildings with greater VI potential. Additionally, the ranking system can be used to increase defensibility of conclusions during VI assessments and long-term stewardship decisions, providing improved risk management and long-term stewardship decisions.