UC San Diego

The atmospheric transport of mineral dust or particulate matter (PM) interacts with global Earth systems at multiple scales and is significantly modified by human activities. Different academic disciplines address unique facets of the environmental and public health significance of dust. However, given the complex composition and emission dynamics of dust sources, especially in arid and semi-arid regions, there is a need for further multiscale and trans-disciplinary research to develop new tools to consider their differential health impacts. In this dissertation, I use multiple geospatial frameworks to study the generation, transport and health impacts of dust, focusing on case studies in California. In chapter 1, I investigate the spatial and temporal variance of mineral dust deposition through a multi-year field study on San Jacinto Peak in Southern California, using low-temperature geochemical tools including flux, major and trace element enrichment, and Positive Matrix Factorization (PMF). I highlight the significant presence of anthropogenically created particles, and the impact of wildfires on deposition rates and metal content. In chapter 2, I perform a scoping review and meta-analysis of relative risks from PM exposure to assess the extent of global knowledge of PM-related cardiorespiratory hospitalizations and mortality in arid and semi-arid environments, investigating how climate plays a role in modifying health outcomes from exposure to PM. In chapter 3, I combine geochemical source apportionment tools (PMF) and an epidemiological two-way fixed effects model to study the association between source-specific PM concentrations and cardiorespiratory hospitalization across California. This study spans a more than 10-year period, and identifies effect modification by climate, air basin, and season. In chapter 4, I summarize environmental justice and anti-colonial frameworks to investigate multi-timescale interactions between human land uses, dust emission, and intergenerational health impacts, with a case study of the Imperial Valley, California, to explore the potential use of this approach. This discussion examines a quantitative accounting method to trace dust impacts on health, connecting specific sources and short-term health impacts to long-time-scale contexts that create land use related dust sources and disproportionate burdens on specific populations.