Ground-based and Airborne Aerosol Studies Over Arid and Marine Regions
Author
Zeider, Kira ThereseIssue Date
2024Advisor
Sorooshian, ArminRamírez-Andreotta, Mónica
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The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.Abstract
Aerosol particles have significant effects throughout the troposphere: they affect human health and safety primarily in the lower levels of the atmosphere and affect the Earth’s radiation balance and cloud formation at higher altitudes. There is a suite of methods to characterize horizontal and vertical compositions of aerosols across the globe, including surface monitoring, airborne data collected via aircraft field campaigns, spaceborne remote-sensors, and reanalysis models. This work focuses first on ground-based methodology of aerosol characterization, specifically through the use of community-engaged research, and second on the combination of airborne research methods to better understand aerosol-cloud-meteorology interactions. The first study used co-created community science data from a legacy industry-adjacent community in Arizona to determine the efficacy of plant leaves (foliar surfaces) to sample aerosol pollutants in ambient air, and by proxy, to serve as low-cost air quality monitors. Using spatial concentration characterization, enrichment factor calculations, and statistical and regression analyses, it was determined that foliar collection is a viable indicator of aerosol contamination with respect to outdoor settled dust, with sampling efficacy comparative to an accepted deposition sampling method. Dust particles laden with toxic elements/contaminants such as arsenic, lead, and cadmium, that have previously been found discharged into nearby soils, waterways, and the atmosphere near fence-line communities, were found in high concentrations compared to naturally occurring levels, which provided support for the research and implementation of low-cost air quality monitors for concerned communities. The second study continued the work from the previous co-created community science study, but was conducted across several Arizona communities, ascertaining the influence of plant family, leaf surface area, and sampling location on foliar collection efficacy. Statistical analyses using the Kruskal-Wallis test led to the conclusion that leaf surface area was the most influential factor for dust deposition sampling compared to the other factors considered. It was also determined that elements toxic to humans at high dosages and from repeated exposure, such as manganese, barium, and aluminum, that were observed in backyard soils were likely to have been transported from long-range sources rather than from local sources. The third study utilized in-situ data, such as aerosol and cloud droplet number concentrations (Na and Nd, respectively) and cloud water (CW) speciation, from six airborne missions carried out between July 2011 and September 2020 and based out of Marina, California, as well as data from space-borne remote sensors and global models. The goal of this study was to better understand the aerosol and cloud characteristics along the California coast during unusual periods of low troposphere southerly wind direction as compared to the region’s typical northerly flow pattern. Submicron Na and CW species representative of fine aerosol pollution (NO3- and non-sea salt (nss) SO42-) and shipping/continental emissions (V, oxalate, NH4+, Ni, and organic and elemental carbon, OC and EC, respectively) were found elevated during periods of southerly flow. Further, clouds were found to have elevated values of Nd and cloud optical thickness (COT), and reduced cloud droplet effective radius (re) during southerly flow conditions. The fourth and final study also utilized airborne in-situ data, on the coast opposite of the U.S. compared to the previous study, as part of the Aerosol Cloud meTeorology Interactions oVer western ATlantic Experiment (ACTIVATE). Important factors for aerosol and cloud characterization, particularly for low clouds, include the degree of coupling between the ocean’s surface and sub-cloud base of the atmospheric marine boundary layer (MBL). While previous studies had quantified coupling threshold values for liquid water potential temperature (θℓ) and water vapor mixing ratio (qt), these were with respect to subtropical subsidence regions home to major stratocumulus cloud decks, like off the U.S. west coast. For the east coast, where there is a variety of marine clouds, this study provided updated coupling thresholds for the northwest Atlantic using vertical profiles of θℓ and qt from 2020-2022 and validated through cloud water species concentrations and aerosol and atmospheric properties. The studies presented in this work illustrate the importance of varied research approaches in the pursuit of protecting human health and safety with respect to air quality. The first two studies utilized co-created community science research to build capacity and empower environmental justice communities in Arizona to address their environmental health concerns using phytotechnologies. The last two studies emphasized the complexities and challenges regarding aerosol-cloud interactions, specifically on both the east and west US coasts, with airborne field experiments. Despite the differences in subject matter and research methodology, the research in this work highlights the usefulness of partnering government-supported research campaigns with community-based research to create better solutions to air quality concerns.Type
Electronic Dissertationtext
Degree Name
Ph.D.Degree Level
doctoralDegree Program
Graduate CollegeChemical Engineering