Electronic Theses and Dissertations

Date

2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Epidemiology

Committee Chair

Chunrong Jia

Committee Member

Athena Davenport

Committee Member

Naser Titu

Committee Member

Xichen Mou

Abstract

Exposure to atmospheric polycyclic aromatic hydrocarbons (PAHs) presents a ubiquitous public health risk and is often disproportionately high in disadvantaged communities. Understanding is still limited regarding the sources, disparities, and health effects of PAH exposures. This dissertation consists of three studies that address these knowledge gaps. The first study aimed to quantify the contributions of multiple exposure pathways to PAH-related cancer risks. Concentrations of PAHs in soil and air were measured in Memphis, TN, from 2016 to 2019. The cumulative cancer risk was 0.423×10-6 among children, with 75% from ingestion. For adults, the risk was 0.546×10-6, predominantly from dermal contact (96%). Vehicle emissions, petrogenic sources, and coal combustion together contributed to over 85% of the cancer risk. The second study aimed to examine disparities in PAH exposures using modeled and monitored data in Shelby County, TN. The modeled data showed that ΣPAH concentrations in African American (AA) concentrated areas were 15.4 ng/m³ higher (p = 0.0037) than in White concentrated areas; however, the monitored data did not show statistically significant differences. Similar results were observed if high- and low- income communities were compared. The third study explored the relationship between breast cancer incidence and environmental factors among 355 AA women in Memphis. Logistic regression identified significant associations between breast cancer risk and proximity to high-traffic areas (OR = 1.636, 95% CI: 1.046–2.560) and Superfund sites (OR = 12.262, 95% CI: 1.814–82.864), which were potential PAH sources. Mediation analyses further revealed that environmental disparities contributed to disparities in breast cancer incidence. These findings provide evidence for future interventions to prevent or control PAH exposures, inform practical actions and regulations to address environmental disparities, and further enhance our understanding of the role of environmental exposure in health disparities.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Open access

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