Explorations into the Composition of Brake Wear Particles from Semi-Metallic and Ceramic Brake Pads
Maxwell Lee,
CU ANYL 1st year

Vehicle based air pollution has always been a major contributor to air pollution from combustion-based exhaust particulate matter and emissions. As vehicle trends shift away from combustion-based drive trains, other sources of vehicle-based pollutants will become the main source of vehicle air pollution. Particularly, particulate matter is of great concern to study because it is known that brake pad wear can be a source of these hazardous particles. While a general idea of elemental composition is known for brake pad particles, the chemical composition of organic particles emitted from braking events is largely unknown. Additionally, there is no general consensus on whether brake pads marketed as “ceramic” and “semi-metallic” differ in elemental composition. These unknowns create multiple issues when attempting to find the concentration of brake pad pollution in the air near areas of high traffic. We found that the elemental composition of “ceramic” and “semi-metallic” brake pads does differ and are linked by the presence of common elements like Iron, Magnesium, and Barium, making these elements potential ways to track brake pollution. Additionally, we discovered that organic particles from brake pads form from unique tribological processes, and that using H/C and O/C ratios may be a possible method for tracking organic brake pad pollution. These results can be used to inform possible field studies near high traffic areas to determine how concentrated brake pollution is in those areas. Ideally, these tracers can be used to find trends in brake pad pollution in the context of environmental justice and show whether there are trends between brake pad pollution concentrations and the health of low-income communities.

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Comparative Analysis of AVIRIS and WorldView-3 SWIR for Geologic Mapping in Anza-Borrego Desert State Park
Jeffrey Price,
CU ANYL 1st year

A geologic map is both a visual depiction of the lithologies and structures occurring at the Earth’s surface and a representation of a conceptual model for the geologic history in a region. The work needed to capture such multifaceted information in an accurate geologic map is time consuming. Remote sensing can complement traditional primary field observations, geochemistry, chronometry, and subsurface geophysical data in providing useful information to assist with the geologic mapping process. Two novel sources of remote sensing data are particularly relevant for geologic mapping applications: decameter-resolution imaging spectroscopy (spectroscopic imaging) and meter-resolution multispectral shortwave infrared (SWIR) imaging. Decameter spectroscopic imagery can capture important mineral absorptions but is frequently unable to spatially resolve important geologic features. Meter-resolution multispectral SWIR images are better able to resolve fine spatial features but offer reduced spectral information. Such disparate but complementary datasets can be challenging to integrate into the geologic mapping process. Here, we conduct a comparative analysis of spatial and spectral scaling for two such datasets: one Airborne Visible/Infrared Imaging Spectrometer—Classic (AVIRIS-classic) flightline, and one WorldView-3 (WV3) scene, for a geologically complex landscape in Anza-Borrego Desert State Park, California. In this talk, I will discuss the physically based portion of our approach: the spectral mixture residual. The mixture residual uses the wavelength-explicit misfit of a linear spectral mixture model to capture low variance spectral signals. For this study area, the spectral mixture residual revealed greater spectral dimensionality in AVIRIS than WorldView (99% of variance in 39 versus 5 residual dimensions). These results illustrate the potential of recent and planned imaging spectroscopy missions to complement high-resolution multispectral imagery—along with field and lab observations—in planning, collecting, and interpreting the results from geologic field work.