The effects of blending ratios on soot formation remain unclear as sustainable aviation fuels (SAF) are introduced to replace fossil fuels and reduce particulate emissions. Small-Angle X-ray Scattering (SAXS) is used to investigate soot primary particles from ethylene, Jet A-1, and SAF blends in laminar diffusion flames. A Bayesian framework with physical constraints analyzes the SAXS data using a pair-correlation-based model, yielding spatially resolved primary particle size distributions. Results highlight the impact of replacing Jet A-1 with SAF on particle size distribution, Porod invariant (proportional to soot volume fraction), and surface-to-volume ratio.

The climatic impact of aviation is a subject of significant scientific scrutiny, encompassing effects beyond direct radiative forcing from carbon dioxide. A substantial component of the effective radiative forcing is attributable to non-CO2 effects, including the formation of contrail-cirrus clouds, for which non-volatile particulate matter (nvPM) emissions act as precursor nuclei. These emissions also degrade local air quality at airports. Therefore, the development of effective mitigation strategies is imperative. Empirical studies have demonstrated that Sustainable Aviation Fuels (SAF) represent a viable mitigation pathway, capable of significantly reducing nvPM mass and number emissions from jet engines.

Real-world emission data of aircrafts is essential for the development of realistic air quality models. In the present work, about 1600 single aircraft exhaust plumes were investigated during two measurement campaigns at Frankfurt Airport as part of the project SOURCE FFR (Study On Ultrafine Particles in the Frankfurt Airport Region). Based on these measurements emission indices for both total and non-volatile particle number as well as NO_x were obtained covering about 70 different aircraft engine types. This dataset provides a valuable source of input parameters for ongoing modelling efforts.

Aircraft operations emit significant particulate matter (PM) and ultrafine particles (UFP), impacting air quality near airports. The Appropriate project assessed emissions at Zürich Airport via laboratory studies, test cell measurements, and a month-long field campaign in 2022. A suite of advanced instruments, including LToF-AMS, EESI-TOF, and VOCUS PTR, quantified non-refractory PM components and volatile organic compounds. Preliminary LToF-AMS data revealed elevated oil-related organic markers (m/z 85/71 > 0.66), suggesting lubrication oil contributions. Coupled with molecular-level EESI and VOCUS data, measurements enable detailed source apportionment of primary and secondary aerosols, providing critical insights into aviation-related atmospheric chemistry and health impacts.