Over the last decades, slow steaming strategies have been adopted by most shipping lines with the aim of reducing fuel costs. At the same time, these have resulted in significant environmental benefits from emissions reductions, which have contributed to a relative reduction to of the footprint of maritime transport, currently accounting for about 3% of the total world carbon dioxide (CO2) emissions. Such initiatives need to be expanded as the maritime transport demand steadily grows and its impacts increase. The maritime transport is also responsible for sulfur, nitrogen and Particulate Matter emissions, which can pose significant threats to public health and resulted in calls from local communities for action. Near port emissions from ships can be classified into three types; those that originate from near-port cruising, manoeuvring and berth emissions. Port authorities tend to develop policies and apply technological solutions to address these types. Slow steaming has been recognised as one of the most promising approaches to reduce cruising emissions. This paper examines the effects of such policies locally and globally, and seeks to answer how to best deploy a vessel speed reduction program for a port authority in order to achieve the highest possible local benefits without compromising on a global level. The economic consequences of adopting such policies are discussed, along with the effects of sulfur emission control areas. The local versus global trade-offs between different pollutants are discussed and the proposed methodology allows the calculation of such trade-offs.