Queueing-driven transportation emissions and near-road exposure at a binational port of entry: An AERMOD assessment

Abstract

Queueing-driven transportation emissions at international ports of entry create localized air pollution hotspots affecting commuters, pedestrians, and facility workers. This study examines the Bridge of the Americas, a U.S.-Mexico port of entry in El Paso, Texas, using continuous Federal Equivalent Method monitoring and AERMOD dispersion modeling to assess traffic-related air pollutants. Monitored PM_2.5 and NO₂ concentrations were elevated at the port compared to a nearby reference site. Modeling showed that concentrations plateau once vehicle queues exceed 270 m, with levels declining tenfold within 200 m of the traffic lanes. Pedestrians experienced 75% of in-lane pollutant concentrations, and toll booth workers 66%. Modeled contributions accounted for 51% of PM_2.5, 147% of PM₁₀, and 7% of NO₂ relative to monitored averages. Findings demonstrate how queue length, traffic mix, and weather impact exposure and support strategies, such as queue management, lane design, and walkway placement, to reduce emissions at border crossings.