Supplementary file 1_Route level and mode resolved emission dispersion analysis of tugboat operations along offshore terminal routes: implications for coastal air quality.docx

<p>This study investigates the potential coastal air quality implications of tugboat operations associated with offshore mooring-buoy routes in Trabzon Port (Black Sea, Türkiye) through a route-level and mode-resolved integrated assessment combining an activity-based emission inventory, AERMOD dispersion modeling, and non-parametric statistical analysis. Harbor craft operating within port basins represent a localized yet influential emission source that may affect both coastal urban air quality and adjacent marine environments.

Emissions of NOx, CO, SO₂, PM, and HC were estimated for two operational routes under cruising and maneuvering modes using a Tier-3 time-in-mode methodology. Annual emissions associated with the shared Route B corridor reached 6.54 t NOx and 2.62 t CO, approximately 18% higher than the corresponding Route C totals. This difference reflects the route-accounting structure because the Port–B segment is traversed by both B-bound operations and C-bound operations continuing toward the more distant offshore terminal.