Aviation Fuel Image
A photo of the DLR ATRA aircraft leaving contrails while using alternative fuels. (Credit: DLR)

Cleaner-burning jet fuels made from sustainable sources can produce 50%-70% fewer ice crystal contrails at cruising altitude, reducing aviation’s impact on the environment, according to research conducted by NASA and the German Aerospace Center (DLR).

Jet engine exhaust includes water vapor and soot particles. As the water vapor cools, it condenses. Ice crystals form when that supercooled water interacts with either exhaust soot or particles naturally present in the air.

By using alternative fuel, jet engines release fewer soot particles, resulting in fewer ice crystal formations. The crystals that do form are larger but that does not create a problem because they fall more quickly and melt in the warmer air below.