Cleaner burning aviation fuels can reduce contrail cloudiness

Burning sustainable aviation fuel blends with low levels of soot-producing aromatic components can result in a 50 to 70% reduction in soot and ice number concentrations and an increase in ice crystal size, suggest measurements of exhaust and contrail characteristics in two aircraft campaigns. Contrail cirrus account for the major share of aviation's climate impact. Yet, the links between jet fuel composition, contrail microphysics and climate impact remain unresolved. Here we present unique observations from two DLR-NASA aircraft campaigns that measured exhaust and contrail characteristics of an Airbus A320 burning either standard jet fuels or low aromatic sustainable aviation fuel blends. Our results show that soot particles can regulate the number of contrail cirrus ice crystals for current emission levels. We provide experimental evidence that burning low aromatic sustainable aviation fuel can result in a 50 to 70% reduction in soot and ice number concentrations and an increase in ice crystal size. Reduced contrail ice numbers cause less energy deposition in the atmosphere and less warming. Meaningful reductions in aviation's climate impact could therefore be obtained from the widespread adoptation of low aromatic fuels, and from regulations to lower the maximum aromatic fuel content.

Automated summary

Burning sustainable aviation fuel blends with low levels of soot-producing aromatic components can significantly reduce ice and ice crystal number concentrations while increasing ice crystal size. This method can result in less energy deposition in the atmosphere and less warming.