Honors Theses
Date of Award
Spring 5-6-2026
Document Type
Undergraduate Thesis
Department
Southern Studies
First Advisor
Courtney Roper
Second Advisor
Andrew Harper
Third Advisor
Hang Nguyen
Relational Format
Dissertation/Thesis
Abstract
This study examines seasonal patterns of particulate matter in the Mississippi Delta using data from PurpleAir sensors, with a focus on particle size distributions across PM₁.₀, PM₂.₅, and PM₁₀. The purpose of this research is to evaluate whether particulate trends in the region reflect signatures consistent with wildfire smoke or are better explained by local environmental and agricultural factors.
Daily average concentrations were analyzed and grouped by season to compare spring and summer conditions. Results show that all particle size fractions increased from spring to summer. However, PM₁₀ concentrations remained consistently higher than PM₂.₅ in both seasons. The PM₂.₅/PM₁₀ ratio increased from 0.85 in spring to 0.93 in summer, indicating a relative increase in fine particles during the summer months, but not a shift to fine particle dominance. PM₁.₀/PM₂.₅ ratios remained relatively stable across both seasons.
These findings differ from typical wildfire smoke signatures, which are characterized by a dominance of fine particles and higher PM₂.₅ contributions relative to PM₁₀. Instead, the observed patterns suggest a mixed-source environment influenced by coarse particulate matter,
likely driven by agricultural activity such as soil disturbance, along with regional humidity contributing to secondary aerosol formation.
This study demonstrates that wildfire-based particulate models may not accurately represent air quality dynamics in the Mississippi Delta. The results highlight the importance of considering regional land use and environmental conditions when interpreting particulate matter data and assessing potential health and environmental impact.
Recommended Citation
Barnett, Abigail E., "Seasonal Variation and Size Distribution of Particulate Matter in the Mississippi Delta: Implications for Source Attribution" (2026). Honors Theses. 3479.
https://egrove.olemiss.edu/hon_thesis/3479