Engineers just mapped a narrow path to greener flying

Flying contributes significantly to greenhouse gas emissions, with a single transatlantic flight producing emissions comparable to an average European heating their home for a year. The aviation industry has taken steps to reduce its emissions but lacks comprehensive data on their effectiveness. Researchers from the German Aerospace Center conducted a study published in Science Advances to evaluate the impact of sustainable aviation fuels and modern engines on aircraft pollution.

Their findings indicate that a combination of alternative fuels and advanced technologies is necessary to minimize particle emissions. Jet engine emissions consist of carbon dioxide and ultrafine particles, which pose a risk to human health and contribute to contrails that trap heat in the atmosphere. Sustainable aviation fuels and lean-burn engines, which utilize a higher air-to-fuel ratio, are both expected to decrease particle emissions.

The researchers analyzed in-flight particulate emissions from two Airbus aircraft, with one using conventional fuel and the other sustainable aviation fuel. Both planes were equipped with cutting-edge engines that reduced soot particle emissions by three orders of magnitude compared to conventional engines. However, under rich-burn conditions, soot emissions remained dependent on fuel hydrogen content.

Additionally, emissions from sustainable fuels increased with sulfur content, and variations occurred even among engines of the same type. This study provides valuable insights for optimizing fuel composition and engine technology, which could enhance aircraft emissions monitoring and reduce the impact of aviation on climate and public health.