Synergistic control of greenhouse gas and air pollutant emissions from ships in global container ports

Greenhouse gas (GHG) emissions from ships operating within ports are a significant contributor to climate change, and co-emitted air pollutants harm coastal ecosystems and public health. Yet much of the literature is fragmented by single-port scope, single-measure evaluation, and baselines that overlook active regulations, which limits comparability and decision relevance. To address these gaps, this study assesses multi-pollutant emissions and mitigation portfolios for the world’s top one hundred container ports. We establish a 2023 baseline reflecting current controls, using global AIS trajectories, Lloyd’s Register ship specifications, regulatory layers for ECAs and regional at-berth rules, and external-cost factors from established databases. We quantify GHG and air-pollution emissions, evaluate the mitigation potential of key measures, and derive port-specific strategies via a decision model. In 2023, ship emissions in major container ports totaled approximately 1.15 × 105 tons of air pollutants (SO2, NOx, PM2.5, CO, NMVOC) and 7.54 × 10⁶ tons of GHGs (CO2, CH4, N2O), with associated external costs of about £1.13 × 104 million. Emissions were dominated by auxiliary engines and boilers during berthing, and Asian ports accounted for over seventy percent of the total. Switching to low-sulfur marine fuels and utilizing shore power are the most effective single measures, each reducing external costs by roughly forty percent, whereas slow steaming and new nitrogen emission control areas have more limited effects. Implemented together, the four measures reduce air pollutants by about sixty percent and GHGs by about thirty-nine percent, lowering external costs to about thirty percent of the baseline. Prioritization varies by port characteristics, including location, scale, vessel mix, approach length, dwell time, and infrastructure readiness, providing decision-relevant guidance for cleaner port operations.