The article analyses in detail the impact of adding n-butane to marine fuel on the emission of harmful compounds in diesel engines used in maritime transport. The applied multi-criteria analysis showed that introducing n-butane as a fuel additive can significantly reduce the emission of substances such as nitrogen oxides (NOx), carbon monoxide (CO) and carbon dioxide (CO2), which consequently reduces the negative impact on the natural environment. In addition, the studies confirm that the mixture does not affect the operational efficiency of engines, which means that it can be used without the need to introduce major changes to the infrastructure or to the vessels themselves. Nevertheless, the authors emphasise that further research is necessary, especially at higher concentrations of n-butane, to optimise this method in terms of long-term ecological and economic benefits and to ensure its full effectiveness. The conclusions indicate the potential of this technology, but they emphasise that it will be crucial to carry out additional tests to minimise the risk of possible negative side effects.