Impact of Sustainable Aviation Fuels on the Emission Indices of Gaseous Species and Particulate Matter

This study analyzes the emission performance of sustainable aviation fuels (SAFs) compared to conventional Jet A-1 fuel across various engine types. The results show that SAFs, especially HEFA and ATJ, significantly reduce emissions of carbon monoxide, hydrocarbons, and particulate matter. For instance, ATJ achieved up to 70% lower particulate number emissions at low thrust in the CFM56 engine. However, SAFs tend to increase nitrogen oxides emissions by 15–20% due to higher combustion temperatures. This effect was less pronounced in engines optimized for SAFs, such as the GE engine using a 50% HEFA blend. While hydrocarbon emissions remained stable in large engines, mini engines showed reductions up to 15% with Camelina HRJ. Carbon monoxide emissions consistently dropped with higher SAF content, especially in low-thrust conditions. The study concludes that SAFs offer strong environmental benefits, though further research is needed to mitigate NO x emissions and optimize fuel-engine compatibility.