Creation of a Sub-slab Soil Gas Cloud by an Indoor Air Source and Its Dissipation Following Source Removal

Chase Holton, Yuanming Guo, Hong Luo, Paul Dahlen, Kyle Gorder, Erik Dettenmaier, Paul C. Johnson

Research output: Contribution to journalArticle

Abstract

It is accepted that indoor sources of volatile organic compounds can confound vapor intrusion (VI) pathway assessment. When they are discovered during pre-sampling inspection, indoor sources are removed and air sampling is delayed, with the assumption that a few hours to a few days are sufficient for indoor source impacts to dissipate. This assumption was tested through the controlled release of SF6 and its monitoring in indoor air and soil gas at a study house over 2 years. Results show that indoor sources generate subsurface soil gas clouds as a result of fluctuating direction in the exchange between soil gas and indoor air and that it may take days to weeks under natural conditions for a soil gas cloud beneath a building to dissipate following indoor source removal. The data also reveal temporal variability in indoor air and soil gas concentrations, long-term seasonal patterns, and dissipation of soil gas clouds over days to weeks following source removal. Preliminary modeling results for similar conditions are consistent field observations. If representative of other sites, these results suggest that a typical 1-3 day waiting period following indoor source removal may not be sufficient to avoid confounding data and erroneous conclusions regarding VI occurrence.

Original languageEnglish (US)
JournalEnvironmental Science and Technology
DOIs
StateAccepted/In press - Jan 1 2018

Fingerprint

soil gas
indoor air
dissipation
slab
Gases
Soils
Air
Vapors
Sampling
Volatile Organic Compounds
air sampling
volatile organic compound
removal
Inspection
Monitoring
sampling
monitoring
modeling

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

Cite this

Creation of a Sub-slab Soil Gas Cloud by an Indoor Air Source and Its Dissipation Following Source Removal. / Holton, Chase; Guo, Yuanming; Luo, Hong; Dahlen, Paul; Gorder, Kyle; Dettenmaier, Erik; Johnson, Paul C.

In: Environmental Science and Technology, 01.01.2018.

Research output: Contribution to journalArticle

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