skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Temporal Changes in Thirdhand Cigarette Smoke Film Composition and Oxidation of Co-existing Surface Film Chemicals
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.  more » « less
Award ID(s):
2018547
PAR ID:
10489765
Author(s) / Creator(s):
;
Publisher / Repository:
Royal Society of Chemistry
Date Published:
Journal Name:
Environmental Science: Atmospheres
ISSN:
2634-3606
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; ; et al (, Environmental Science: Atmospheres)
    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. 
    more » « less
  2. ; ; ; ; ; ; ; ; ; (, ACS ES&T Air)
    Asphalt-related emissions are an understudied source of reactive organic compounds with the potential to form organic aerosol (OA). Ambient aerosol mass spectrometry (AMS) measurements of asphalt-related aerosols near a month-long road paving project showed enhanced ambient OA concentrations with a mix of primary and secondary OA signatures. For comparison, gas-phase emissions from real-world road asphalt samples at application (e.g., 140 °C) and in-use (e.g., 60 °C) temperatures were injected into an environmental chamber and an oxidation flow reactor to simulate varying degrees of oxidative aging while measuring their gas- and aerosol-phase oxidation products. Secondary OA formation was observed via both self-nucleation and condensation, with chemical properties dependent on asphalt temperature and reaction conditions. The chemical composition of less-aged asphalt-related OA observed in outdoor and laboratory measurements was similar to OA from other petrochemical-based sources and hydrocarbon-like OA source factors observed via AMS in previous urban studies. The composition of aged OA varied with the degree of oxidation, similar to oxidized OA factors observed in ambient air. Taken together, these field and laboratory observations suggest that contributions to urban OA during and after application may be challenging to deconvolve from other traditional sources in ambient measurements. 
    more » « less
  3. ; (, Journal of Vacuum Science & Technology A)
    Spatial atomic layer deposition (SALD) is a powerful thin-film deposition technique to control surfaces and interfaces at the nanoscale. To further develop SALD technology, there is need to deepen our understanding of the effects that process parameters have on the deposited film uniformity. In this study, a 3D computational model that incorporates laminar-flow fluid mechanics and transport of diluted species is developed to provide insight into the velocity streamlines and partial-pressure distributions within the process region of a close-proximity atmospheric-pressure spatial atomic layer deposition (AP-SALD) system. The outputs of this transport model are used as the inputs to a surface reaction model that simulates the self-limiting chemical reactions. These coupled models allow for prediction of the film thickness profiles as they evolve in time, based on a relative depositor/substrate motion path. Experimental validation and model parameterization are performed using a mechatronic AP-SALD system, which enable the direct comparison of the simulated and experimentally measured geometry of deposited TiO2 films. Characteristic features in the film geometry are identified, and the model is used to reveal their physical and chemical origins. The influence of custom motion paths on the film geometry is also experimentally and computationally investigated. In the future, this digital twin will allow for the capability to rapidly simulate and predict SALD behavior, enabling a quantitative evaluation of the manufacturing trade-offs between film quality, throughput, cost, and sustainability for close-proximity AP-SALD systems. 
    more » « less
  4. ; ; ; ; ; ; ; (, Applied Physics Letters)
    We present nanoscale friction measurements performed on sputter-deposited high entropy alloy (HEA) sulfide thin films [(VNbTaMoW)S2] via atomic force microscopy. The results reveal (i) the influence of deposition time on the film morphology and (ii) the presence of isolated areas of low friction on film surfaces. We compare the friction results on HEA sulfide thin films with those on a prototypical solid lubricant, sputter-deposited molybdenum disulfide (MoS2), and find that they are superior in terms of lubricative performance. Variable temperature x-ray diffraction, performed up to 973 K, reveals that HEA sulfide thin films exhibit improved oxidation resistance when compared with MoS2 films. Combined, our results show that HEA sulfide thin films have considerable potential as oxidation-resistant solid lubricant coatings. 
    more » « less
  5. ; (, Scientific Reports)
    Abstract The design of multifunctional alloys with multiple chemical components requires controllable synthesis approaches. Physical vapor deposition techniques, which result in thin films (<1 μm), have previously been demonstrated for micromechanical devices and metallic combinatorial libraries. However, this approach deviates from bulk-like properties due to the residual stress derived in thin films and is limited by total film thickness. Here, we report a route to obtain ternary Ni-Mn-Sn alloy thick films with controllable compositions and thicknesses by annealing electrochemically deposited multi-layer monatomic (Ni, Mn, Sn) films, deposited sequentially from separate aqueous deposition baths. We demonstrate (1) controllable compositions, with high degree of uniformity, (2) smooth films, and (3) high reproducibility between film transformation behavior. Our results demonstrate a positive correlation between alloy film thicknesses and grain sizes, as well as consistent bulk-like transformation behavior. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email