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The composition of air-exposed surfaces can have a strong impact on air quality and chemical exposure in the indoor environment. Third hand smoke (THS), which includes surface-deposited cigarette smoke residue along with the collection of gases evolved from such residues, is becoming increasingly recognized as an important source of long-term tobacco smoke exposure. While studies have described gas/surface partitioning behaviour and some multiphase reaction systems involving THS, the possibility of time-dependent changes in chemical composition due to chemical reactivity that is endogenous to the deposited film has yet to be investigated. In this study, sidestream cigarette smoke was allowed to deposit on glass surfaces that were either clean or pre-coated with chemicals that may be oxidized by reactive oxygen species found in the smoke. Surface films included a low volatility antioxidant, tris(2-carboxyethyl)phosphine (TCEP), and two compounds relevant to surface films found within buildings, oleic acid (OA) and squalene (SQ). Upon deposition, oxidation products of nicotine, TCEP, OA, and SQ were formed over time periods of hours to weeks. The inherent oxidative potential of cigarette smoke deposited as a THS film can therefore initiate and sustain oxidation chemistry, transforming the chemical composition of surface films over long periods of time after initial smoke deposition. An interpretation of the THS oxidation results is provided in the context of other types of deposited particulate air pollutants with known oxidative potential that may be introduced to indoor environments. Continued study of THS and deposited surface films found indoors should consider the concept that chemical reservoirs found on surfaces may be reactive, that the chemical composition of indoor surface films may be time-dependent, and that the deposition of aerosol particles can act as a mechanism to initiate oxidation in surface films.
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Emerging investigator series: deposited particles and human lung lining fluid are dynamic, chemically-complex reservoirs leading to thirdhand smoke emissions and exposure
Thirdhand smoke (THS) persists in locations where smoking previously occurred and can be transported into non-smoking environments, leading to non-smoker exposure. Laboratory experiments using high-resolution mass spectrometry demonstrate that deposited particulate matter (PM) and smoke-exposed surrogate lung lining fluid (LLF) are substantial, chemically-complex reservoirs of gas-phase THS emissions, including hazardous air pollutants, polycyclic aromatic compounds, and nitrogen/oxygen-containing species. Both PM and LLF are persistent real-world THS reservoirs that chemically evolve over time, and can act as vehicles for the transport and emission of reactive pollutants and their reaction byproducts (e.g., acrolein). Deposited PM on clothes, furnishings, bodies, and/or airways will emit volatile to semi-volatile gases over long lifetimes, which can re-partition to other indoor materials and increase their overall persistence. On the other hand, LLF off-gassing consists predominantly of volatile organic compounds in amounts influenced by their aqueous solubilities, and their persistence in breath will be prolonged by re-distribution across internal aqueous reservoirs, as corroborated by multicompartment modeling in this study.
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- PAR ID:
- 10348417
- Date Published:
- Journal Name:
- Environmental Science: Atmospheres
- ISSN:
- 2634-3606
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D1EA00107H
