Ship Air Emission and Their Air Quality Impacts in the Panama Canal Area: An Integrated AIS-Based Estimation During Hotelling Mode in Anchorage Zone

This study presents an integrated assessment of anchorage-related emissions and air quality impacts in the Panama Canal region through Automatic Identification System (AIS) data, bottom-up emission estimation, and atmospheric dispersion modeling. One year of terrestrial AIS observations (July 2024–June 2025) captured 4641 vessels with highly variable waiting times: mean 15.0 h, median 4.9 h, with maximum episodes exceeding 1000 h. Annual emissions totaled 1,390,000 tons of CO2, 20,500 tons of NOx, 4250 tons of SO2, 656 tons of PM10, and 603 tons of PM2.5, with anchorage activities contributing 497,000 tons of CO2, 7010 tons of NOx, 1520 tons of SO2, 232 tons of PM10, and 214 tons of PM2.5. Despite the main engines being shut down during anchorage, these activities consistently accounted for 34–36% of the total emissions across all pollutants. High-resolution emission mapping revealed hotspots concentrated in anchorage zones, port berths, and canal approaches. Dispersion simulations revealed strong meteorological control: northwesterly flows transported emissions offshore, sea–land breezes produced afternoon fumigation peaks affecting Panama City, and southerly winds generated widespread onshore impacts. These findings demonstrate that anchorage operations constitute a major source of shipping-related pollution, highlighting the need for operational efficiency improvements and meteorologically informed mitigation strategies.