Substantial aircraft contrail formation at low soot emission levels

Substantial aircraft contrail formation at low soot emission levels | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Physical Sciences - Article Substantial aircraft contrail formation at low soot emission levels Christiane Voigt, Raphael Märkl, Daniel Sauer, Rebecca Dischl, and 26 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6559440/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Apr, 2026 Read the published version in Nature → Version 1 posted You are reading this latest preprint version Abstract Contrail cirrus are a major contributor to the climate forcing from aviation. Yet, the number of contrail ice crystals forming behind aircraft with modern lean-burn engines is unknown. Theory spans a five orders of magnitude range in ice crystal numbers – rendering related climate effects unpredictable. Here, we present first in-flight observations of contrails formed behind an aircraft with lean-burn engine technology. We find a massive reduction in soot particle number emissions, three orders of magnitude lower than soot emissions from conventional rich-quench-lean engines. In contrast, volatile particle number emissions - as well as contrail ice crystal numbers - exceed 10^15 particles per kilogram of burned fuel. We provide first experimental evidence and theoretical explanations for contrail ice activation on volatile aerosol in the absence of soot. Our results demonstrate the impact of lean-burn engine configurations, fuel composition, and ambient conditions on contrail ice crystal numbers. The integration of our data in models will enable to reliably predict the fleet-wide contrail climate effect. Our findings point to the need to minimize volatile particle emissions and affect industrial decisions on engine and fleet design for competitive and clean future aviation. Earth and environmental sciences/Environmental sciences/Environmental impact Earth and environmental sciences/Climate sciences/Atmospheric science Full Text Additional Declarations Yes there is potential Competing Interest. CR, KS, GLC, JM and ERE are employed by Airbus, JZ is employed by General Electric, AR is employed by CFM Safran. All other authors declare that they have no conflict of interest. Cite Share Download PDF Status: Published Journal Publication published 01 Apr, 2026 Read the published version in Nature → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6559440","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":453392840,"identity":"baf4278e-74d0-4064-aa48-dc1b746ac2b5","order_by":0,"name":"Christiane 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