Date of Award

5-4-2021

Degree Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

Public Health

First Advisor

Dr. Christa Watson-Wright

Second Advisor

Dr. Christina Fuller

Third Advisor

Dr. Ruiyan Luo

Abstract

Traffic-related air pollution (TRAP) affects approximately 45 million individuals who live within 300 feet of a major highway, resulting in adverse respiratory and cardiovascular outcomes (e.g., asthma, inflammation). Recent studies indicate that green infrastructure reduces aerosol concentrations and potentially limits TRAP-related toxicity. We hypothesized that green infrastructure might mitigate reactive oxygen species (ROS) generation, oxidative stress, cytokine secretion, and potential inflammation and injury in human primary small airway epithelial cells (SAEC) associated with similar respiratory pathologies, including asthma. TRAP was monitored at five Atlanta locations (S1: green barrier; S2: no barrier; S3: combination barrier; S4: no barrier; S5: green barrier) next to and behind barriers using continuous instrumentation, and sampled particulate matter (PM) was collected on pre-weighed polytetrafluoroethylene (PTFE) filters. The collected PM was extracted and prepared for toxicological assessments, including CellROXĀ®, total glutathione (GSH), and MTS assays, which measured ROS production, oxidative stress, and cellular viability, respectively, using SAEC following a 48-hour exposure period. Additionally, the Human Cytokine Array Proinflammatory Focused 15-plex (HDF15) was used to evaluate the secretion of pro-inflammatory cytokines, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-š¯›¼). Preliminary in vitro toxicological analyses revealed that sites with green barriers (e.g., S1, S5) decreased TRAP-induced impacts on oxidative stress and cytokine secretion in SAEC. However, there was no reduction in cell viability following PM exposures. Additionally, a site with a combination barrier (e.g., S3) decreased GM-CSF, IL-8, and TNF-š¯›¼ cytokine secretion in SAEC. TRAP exposures may elicit harmful pulmonary mechanisms, including inflammation and oxidative stress in lung epithelial cells over time. This work suggests green barriers may influence the biological activity of PM. In sum, green barriers may play a role in mitigating TRAP-mediated respiratory health effects.

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