Evaluating Indoor Air Chemical Diversity, Indoor-to-Outdoor Emissions, and Surface Reservoirs Using High-Resolution Mass Spectrometry

Roger Sheu, Claire F. Fortenberry, Michael J. Walker, Azin Eftekhari, Christof Stönner, Alexa Bakker, Jordan Peccia, Jonathan Williams, Glenn C. Morrison, Brent J. Williams, Drew R. Gentner

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Detailed offline speciation of gas- and particle-phase organic compounds was conducted using gas/liquid chromatography with traditional and high-resolution mass spectrometers in a hybrid targeted/nontargeted analysis. Observations were focused on an unoccupied home and were compared to two other indoor sites. Observed gas-phase organic compounds span the volatile to semivolatile range, while functionalized organic aerosols extend from intermediate volatility to ultra-low volatility, including a mix of oxygen, nitrogen, and sulfur-containing species. Total gas-phase abundances of hydrocarbon and oxygenated gas-phase complex mixtures were elevated indoors and strongly correlated in the unoccupied home. While gas-phase concentrations of individual compounds generally decreased slightly with greater ventilation, their elevated ratios relative to controlled emissions of tracer species suggest that the dilution of gas-phase concentrations increases off-gassing from surfaces and other indoor reservoirs, with volatility-dependent responses to dynamically changing environmental factors. Indoor-outdoor emissions of gas-phase intermediate-volatility/semivolatile organic hydrocarbons from the unoccupied home averaged 6-11 mg h-1, doubling with ventilation. While the largest single-compound emissions observed were furfural (61-275 mg h-1) and acetic acid, observations spanned a wide range of individual volatile chemical products (e.g., terpenoids, glycol ethers, phthalates, other oxygenates), highlighting the abundance of long-lived reservoirs resulting from prior indoor use or materials, and their gradual transport outdoors.

Original languageEnglish (US)
Pages (from-to)10255-10267
Number of pages13
JournalEnvironmental Science and Technology
Issue number15
StatePublished - Aug 3 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society.


  • aerosols
  • atmospheric chemistry
  • emissions of volatile chemical products
  • indoor air quality
  • personal care products
  • surface emissions
  • ventilation
  • volatile organic compounds
  • whole-house emission rates


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