Protecting public health at international border crossings requires clearer evidence on exposure to vehicle-related air pollution. This project measures fine particulate matter (PM2.5) concentrations at different times of day and locations within selected international border crossings to assess potential exposure for cross-border travelers, pedestrians, and United States Customs and Border Protection officials working in inspection booths. The analysis examines relationships among PM2.5 levels, traffic volume, congestion, monitoring distance, and ambient conditions. Identifying statistically significant correlations will support improved understanding of where and when exposure is highest and inform data-driven strategies to predict pollution patterns and guide mitigation efforts at border crossings.