Characterization of Ground-Based Particle Emissions from an Airbus A350-900 Operating on Conventional and Sustainable...

Characterization of total particle emissions from an Airbus A350-900 during the ECLIF3 campaign is presented. Ground measurements ∼24.5 m behind the engine were conducted on three fuels: Jet A-1, HEFA-SPK, and a HEFA Jet A-1 mix. Data include number-mobility size distributions of total and nonvolatile PM (tPM and nvPM), nvPM mass, and size-resolved volatile PM (vPM) mass. LII analysis estimated primary particle size (d_p) and specific surface area (SSA). At small sizes and low power, vPM number contributed up to 50% of tPM, with high-sulfur fuels producing the largest number of vPM and tPM. Fuels with higher hydrogen and lower aromatic content had smaller nvPM aggregate sizes (D_p) and lower mass, but larger d_p, indicating more compact particles. SSA ranged from 160-200 m²/g, varied nonlinearly with thrust, and was lower for high-hydrogen fuels, potentially affecting toxicity. Combined data from this study and others revealed a strong inverse correlation between d_p/D_p ratio vs D_p, relevant for ice nuclei (IN) modeling and climate impacts. vPM mass was dominated by lubrication oil, highly variable at low thrust, and wind-direction dependent; thus, even with Net Zero fuels (no sulfur, high hydrogen, no aromatics), engines may still emit IN via lubrication oil.