UAlbany Atmospheric Scientist Contributes to International Study on Contrail Formation

By Mike Nolan

ALBANY, N.Y. (April 14, 2026) — Fangqun Yu, a senior research faculty member at the University at Albany’s Atmospheric Sciences Research Center, has been studying the microphysics of contrail formation for more than two decades.

Contrails, the thin white streaks often seen trailing behind airplanes, form through a complex process involving the mixing of hot exhaust gases with cold air. Before dissipating, they trap heat that would otherwise be released into space, contributing significantly to climate change.

In a new collaborative study, co-authored by Yu and published in Nature, an international team of researchers found that modern “lean-burn” aircraft engines—designed to reduce soot pollution by up to 1,000 times — still produce the conditions necessary for contrail formation.

For years, scientists hoped that reducing soot emissions would significantly limit contrail formation. This new study upends that assumption.

“Since soot particles from regular aircraft engines have been recognized to act as starting nuclei for the formation of contrail ice particles, the aviation community had hoped that the cleaner engines would reduce the formation and thus warming effect of contrails,” Yu said. “However, the measurements reported in this paper show for the first time that modern cleaner engines cut soot, but not contrails.”

Cutting Soot Alone Won’t Stop Contrails

The researchers combined real-world aircraft measurements with advanced atmospheric modeling to understand how contrails form under modern engine conditions.

To interpret their findings, they used Yu’s physics-based contrail microphysics model, which simulates how particles form and evolve in aircraft plumes under different atmospheric conditions. By integrating the new measurement data into the model, they were able to test whether their simulations matched observed behavior.

Even when soot was drastically reduced, volatile particles formed from gases in the exhaust still enabled contrails to form, confirming the model predictions.

Yu says that a better understanding of volatile particles formed in jet engine exhaust will be crucial when designing the next generation of aircraft engines. 

“Unlike soot particles, volatile particles formed in jet engine exhaust are currently unregulated,” Yu said. “In addition, previous assessments that did not account for contrail formation from volatile particles may underestimate the global warming effects of contrails.”

The study also found that other materials linked to fuel composition and engine oils can form particles that lead to contrails.

“Both measurements and model simulations reported in this paper show that reduction of fuel sulfur content and emission of organic species, including engine oil molecules, can reduce aviation’s climate impact, although the level of reduction under different conditions remains to be further studied,” Yu said.

Reducing Aviation’s Climate Impact

Outside of this study, Yu is exploring a new technique that involves adding a tiny amount of ice-nucleating particles into aircraft engine exhaust, which could make contrails far less harmful by shortening their lifespan.

He was recently awarded $1.5 million from the Simons Foundation, a private organization that supports science and mathematics research, in part to study this contrail reduction technique.

“Our previous research based on model simulations has already predicted that volatile particles can dominate contrail ice particle formation when soot is cut to a very low level,” Yu said. “This new study enhances the robustness of our model, which is being used to explore ways to make contrails less harmful by shortening their lifespan.”

The study was conducted by researchers from institutions including the German Aerospace Center, Airbus, Safran Aircraft Engines, GE Aerospace, and the French Aerospace Lab.