Surface reservoirs dominate dynamic gas-surface partitioning of many indoor air constituents

Chen Wang; Douglas B Collins; Caleb Arata; Allen H Goldstein; James M Mattila; Delphine K Farmer; Laura Ampollini; Peter F DeCarlo; Atila Novoselac; Marina E Vance; William W Nazaroff; Jonathan P D Abbatt

doi:10.1126/sciadv.aay8973

Surface reservoirs dominate dynamic gas-surface partitioning of many indoor air constituents

Sci Adv. 2020 Feb 19;6(8):eaay8973. doi: 10.1126/sciadv.aay8973. eCollection 2020 Feb.

Authors

Chen Wang¹, Douglas B Collins^{1

2}, Caleb Arata^{3

4}, Allen H Goldstein^{4

5}, James M Mattila⁶, Delphine K Farmer⁶, Laura Ampollini⁷, Peter F DeCarlo^{7

8

9}, Atila Novoselac¹⁰, Marina E Vance¹¹, William W Nazaroff⁵, Jonathan P D Abbatt¹

Affiliations

¹ Department of Chemistry, University of Toronto, Toronto, ON, Canada.
² Department of Chemistry, Bucknell University, Lewisburg, PA, USA.
³ Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
⁴ Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA.
⁵ Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, CA, USA.
⁶ Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
⁷ Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, PA, USA.
⁸ Department of Chemistry, Drexel University, Philadelphia, PA, USA.
⁹ Department of Environmental Health and Engineering, Johns Hopkins University, 3400 N. Charles St. Baltimore, MD 21218, USA.
¹⁰ Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX, USA.
¹¹ Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA.

Abstract

Human health is affected by indoor air quality. One distinctive aspect of the indoor environment is its very large surface area that acts as a poorly characterized sink and source of gas-phase chemicals. In this work, air-surface interactions of 19 common indoor air contaminants with diverse properties and sources were monitored in a house using fast-response, on-line mass spectrometric and spectroscopic methods. Enhanced-ventilation experiments demonstrate that most of the contaminants reside in the surface reservoirs and not, as expected, in the gas phase. They participate in rapid air-surface partitioning that is much faster than air exchange. Phase distribution calculations are consistent with the observations when assuming simultaneous equilibria between air and large weakly polar and polar absorptive surface reservoirs, with acid-base dissociation in the polar reservoir. Chemical exposure assessments must account for the finding that contaminants that are fully volatile under outdoor air conditions instead behave as semivolatile compounds indoors.

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