###### Abstract  
In order to achieve the International Air Transport Association's (IATA) goal of achieving net-zero emissions in the aviation industry by 2050, there has been a growing emphasis globally on the technological development and practical application of sustainable aviation fuels (SAFs). Discrepancies in feedstock and production processes result in differences in composition between SAFs and traditional aviation fuels, ultimately affecting the emission performance of the two types of fuel. This paper discusses the impact of CO\({}_{2}\)/NO\({}_{x}\)/SO\({}_{2}\)/CO/PM/UHC emissions from the aviation industry on the natural environment and human healthy by comparing the two types of fuel under the same conditions. Fuel combustion is a complex process in the combustor of an engine, which transfers chemical energy into heat energy. The completeness of combustion is related to the fuel properties, including spray, evaporation, and flammability. Therefore, engine performance is not only affected by fuel performance, but also interacts with engine structure and control laws. The CO\({}_{2}\) emissions of SAFs differ significantly from traditional aviation fuels from a lifecycle analysis perspective, and most SAFs can reduce CO\({}_{2}\) emissions by 41-89%. Compared with traditional aviation fuels, SAFs and blended fuels can significantly reduce SO\({}_{2}\) and PM emissions. Pure Fischer-Tropsch hydropcessed synthesized paraffinic kerosine (FT-SPK) can reduce SO\({}_{2}\) and PM emissions by 92% and 70-95% respectively, owing to its extremely low sulfur and aromatic compound content. In contrast, the differences in NO\({}_{x}\) emissions between the two types of fuel are not significant, as their generation mechanisms largely stem from thermal drive and turbulent flow in the combustor, with emissions performance being correlated to power output and flame temperature profile in engine testing. CO and UHC emissions are related to engine operating conditions and the physical/chemical properties of the SAFs, with no significant upward or downward trend. Therefore, SAFs have significant advantages over conventional aviation fuels in terms of CO\({}_{2}\), SO\({}_{2}\), and PM emissions, and can effectively reduce the hazards of aviation to the environment and human health. SAFs; conventional aviation fuels; aviation emissions; LCA; engine +
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is significant room for progress in the development of SAF technology [3; 4]. Technologies such as electric, hybrid, and hydrogen-powered aircraft face numerous technical barriers, including powerplant innovation, hydrogen storage and transportation, and airport infrastructure redevelopment, making widespread adoption by 2050 challenging. The advantage of SAFs lies in their ability to serve as a \"drop-in\" replacement, without requiring changes to existing engine and combustion chamber designs. SAF production in 2024 is expected to triple compared with 2023, reaching 1.5 million tons (0.53% of 2024 aviation fuel demand), with a projected increase to 62 million tons globally by 2030 [5]. Reports indicate that the global airline market will grow at a compound annual growth rate (CAGR) of 9.3% from 2022 to 2030, with China's CAGR at 11.2% [6]. Given the aviation industry's rapid growth and the significant volume of traditional aviation fuel usage, detailed understanding of the emission performance of SAFs is crucial to achieving Fly Net Zero. Unlike conventional, petroleum-based aviation fuels, SAFs can be derived from energy crop biomass, waste oils, or solid agricultural residues [7; 8; 9]. These renewable materials can capture and sequester atmospheric CO\({}_{2}\) during their growth, creating a closed-loop carbon cycle upon combustion and thereby reducing net carbon emissions. From the perspectives of raw materials and preparation processes, nine bio-jet fuel production pathways have been certified according to ASTM D7566. Consequently, the composition of SAFs differs from traditional aviation fuels.