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Characterizing the chemical heterogeneity of native urban films


EMSL Project ID
49962

Abstract

Environmental surface films (urban films) are ubiquitous coatings on exterior surfaces that form as particulate or molecular biogenic and anthropogenic emissions deposit from the atmosphere onto surfaces. These films cover nearly all impervious surfaces and build to thicknesses that range from 100’s of nm to 10,000's of nm (several thousandths of an inch) and spread over large areas to create a significant volume that serves as a reservoir for persistent atmospheric pollutants. The absorption of pollutants into these films significantly affects their fate and transport as well as human and environmental health. A sponge-like analogy has been suggested, in which the surface films absorb pollutant species during cool, dry weather, and release them during warmer weather or rain events. The morphology and maturation of these films is poorly defined but significantly impacts their ability to 1) partition pollutant species from the atmosphere, 2) act as a matrix for chemical transformation, and 3) release the pollutants, or their degradation products, back into the environment. Our group has collected samples of urban films and conducted preliminary analysis of their morphology and chemical composition. This Rapid Access User Proposal would provide access to additional mass spectral characterization to address remaining questions about these samples. These analysis techniques are not available at the PI’s institution. Primary goals are to create spatially resolved chemical maps of the film surface, and to conduct depth profiles of film chemical components. We predict that more mature films will be increasingly oxidized, affecting film polarity and its interactions with various classes of pollutants. These results serve major goals to define urban film culpability in broad environmental issues including transport, storage, and transformation of pollutant species. Outcomes of this work will support primary publications from the PI’s group in this area, as well as funding applications to NSF and DOD.

Project Details

Project type
Limited Scope
Start Date
2017-08-28
End Date
2017-10-28
Status
Closed

Team

Principal Investigator

Scott Shaw
Institution
University of Iowa

Team Members

Christopher Anderton
Institution
Environmental Molecular Sciences Laboratory

Related Publications

Grant J.S., P.M. Richards, C.R. Anderton, Z. Zhu, T.E. Mattes, and S.K. Shaw. 2019. "Passively Sampled Environmental Films Show Geographic Variability and Host a Variety of Microorganisms." ACS Earth and Space Chemistry 3, no. 12:2726-2735. PNNL-SA-148657. doi:10.1021/acsearthspacechem.9b00234
Grant, J.S.; Shaw, S.K. Native urban films? spatial and chemical heterogeneity reported by microscopy and SIMS analysis. From Abstracts of Papers, 255th ACS National Meeting, New Orleans, LA, United States, March 18-22, 2018. COLL 788.
Grant J.S., Z. Zhu, C.R. Anderton, and S.K. Shaw. 2019. "The Chemical and Physical Morphology of Passively Sampled Environmental Films." Environmental Science & Technology. PNNL-SA-139413. doi:10.1021/acsearthspacechem.8b00158