title: Identification of Alternative Vapor Intrusion Pathways Using Controlled Pressure Testing, Soil Gas Monitoring, and Screening Model Calculations.
abstract: Vapor intrusion (VI) pathway assessment and data interpretation have been guided by an historical conceptual model in which vapors originating from contaminated soil or groundwater diffuse upward through soil and are swept into a building by soil gas flow induced by building underpressurization. Recent studies reveal that alternative VI pathways involving neighborhood sewers, land drains, and other major underground piping can also be significant VI contributors, even to buildings beyond the delineated footprint of soil and groundwater contamination. This work illustrates how controlled-pressure-method testing (CPM), soil gas sampling, and screening-level emissions calculations can be used to identify significant alternative VI pathways that might go undetected by conventional sampling under natural conditions at some sites. The combined utility of these tools is shown through data collected at a long-term study house, where a significant alternative VI pathway was discovered and altered so that it could be manipulated to be on or off. Data collected during periods of natural and CPM conditions show that the alternative pathway was significant, but its presence was not identifiable under natural conditions; it was identified under CPM conditions when measured emission rates were 2 orders of magnitude greater than screening-model estimates and subfoundation vertical soil gas profiles changed and were no longer consistent with the conventional VI conceptual model.
authors.affiliation: School of Sustainable Engineering and the Built Environment, Ira A Fulton Schools of Engineering, Arizona State University , Tempe, Arizona 85287, United States.
authors.forename: Yuanming
authors.initials: Y
authors.lastname: Guo
authors.affiliation: School of Sustainable Engineering and the Built Environment, Ira A Fulton Schools of Engineering, Arizona State University , Tempe, Arizona 85287, United States.|CH2M , 9193 South Jamaica Street, Englewood, Colorado 80112, United States.
authors.forename: Chase
authors.initials: C
authors.lastname: Holton
authors.affiliation: School of Sustainable Engineering and the Built Environment, Ira A Fulton Schools of Engineering, Arizona State University , Tempe, Arizona 85287, United States.|Chevron Energy Technology Company , 1200 Smith Street, Houston, Texas 77002, United States.
authors.forename: Hong
authors.initials: H
authors.lastname: Luo
authors.affiliation: School of Sustainable Engineering and the Built Environment, Ira A Fulton Schools of Engineering, Arizona State University , Tempe, Arizona 85287, United States.
authors.forename: Paul
authors.initials: P
authors.lastname: Dahlen
authors.affiliation: Restoration Installation Support Team, Hill Air Force Base , 7290 Weiner Street, Building 383, Hill AFB, Utah 84056, United States.
authors.forename: Kyle
authors.initials: K
authors.lastname: Gorder
authors.affiliation: Restoration Installation Support Team, Hill Air Force Base , 7290 Weiner Street, Building 383, Hill AFB, Utah 84056, United States.
authors.forename: Erik
authors.initials: E
authors.lastname: Dettenmaier
authors.affiliation: School of Sustainable Engineering and the Built Environment, Ira A Fulton Schools of Engineering, Arizona State University , Tempe, Arizona 85287, United States.|Department of Civil and Environmental Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Johnson
mesh_terms: D004787:Environmental Pollution; D005740:Gases; D060587:Groundwater / Q000737:chemistry; D006798:Housing; D008962:Models, Theoretical; D011312:Pressure; D012987:Soil / Q000737:chemistry
chemical_list: D005740:Gases; D012987:Soil