Summary

Researchers from the Paul Scherrer Institute (PSI) conducted two measurement campaigns (Winter 2022, Summer 2024) to investigate air quality in the vicinity of Runway 28 at Zurich Airport. They demonstrated that aircraft emit ultrafine aerosol particles (UFP) under 100 nanometers during takeoff and landing – with peak values up to 300,000 particles per cubic centimeter of air. New is the detection of lubricating oil adhering to these particles. Real-time measurement via spectrometry enabled, for the first time, direct attribution of emissions to individual aircraft movements and showed that landings produce stronger particle peaks than takeoffs.

People

  • Sarah Tinorua (Study Author, PSI Center for Energy and Environmental Sciences)
  • Benjamin Brem (Study Lead, PSI Center for Energy and Environmental Sciences)

Topics

  • Air traffic and air quality
  • Ultrafine particles (UFP)
  • Lubricating oil emissions
  • Emission reduction
  • Sustainable Aviation Fuel (SAF)

Clarus Lead

The study provides real-time evidence for a previously underestimated emission problem: lubricating oil in breathable air around airports. While high concentrations of ultrafine particles were known, the detection of lubricants in exhaust is health-relevant, as their long-term effects have not yet been researched. The Federal Office of Civil Aviation funded the research and is already advancing international discussions on emission limit values – a signal for possible regulatory measures in air traffic.

Detailed Summary

PSI researchers positioned measurement stations approximately one kilometer downwind of Runway 28 and captured fine dust in real-time using spectrometry. This represented a methodological advance over traditional daily collection: each time an aircraft flew past at 80–100 meters altitude, the instruments registered a sharp increase in UFP concentration. The turbine exhaust is pushed downward by the wing's downwash, directly into the measurement device. Only at flight altitudes above 300 meters do the particles disperse in the atmosphere and become unmeasurable.

Chemical analysis revealed a mixture of solid soot and volatile sulfate, both combustion products of the gas turbine. Lubricating oil was detected in real-time for the first time – a semi-volatile organic substance that enters the exhaust in some engines. While earlier measurements at Frankfurt Airport had found lubricating oil in daily averages, the PSI method enabled direct attribution to individual aircraft. Landings produced more pronounced peaks than takeoffs; during takeoffs, peaks only occurred when wind carried the particle cloud to the measurement station. Strong wind led to higher particle numbers, as weak air movement favors agglomeration and formation of larger particles.

The researchers identified several solution approaches: low-sulfur kerosene reduces fine dust, as sulfur compounds make up a large portion of volatile pollutants. Sustainable Aviation Fuel (SAF) contains no sulfur and fewer soot precursor substances, thus burns cleaner. Zurich Airport has already implemented measures: auxiliary turbines are prohibited; aircraft instead use power supply from the gate. In the long term, electric tugs during taxiing could save substantial amounts of incompletely burned kerosene.

Key Findings

  • Aircraft emit up to 300,000 ultrafine particles per cubic centimeter of air during takeoff and landing – ten times the nighttime background value.
  • Lubricating oil was detected in real-time in aircraft emissions for the first time; long-term health effects have not yet been researched.
  • Low-sulfur kerosene and Sustainable Aviation Fuel (SAF) could significantly reduce fine dust emissions.

Critical Questions

  1. Source Validity: The measured values come from only two multi-week campaigns (Winter 2022, Summer 2024). How representative are these data for year-round emission patterns, particularly under different weather conditions and flight volumes?

  2. Lubricating Oil Causality: The study detects lubricating oil in emissions, but not in all aircraft types. Which engine models or maintenance conditions are responsible, and how can this be systematically regulated?

  3. Health Relevance: The statement that lubricating oil long-term effects are "not yet comprehensively researched" is cautiously worded. What epidemiological studies of residents or airport employees exist or are planned?

  4. SAF Feasibility: SAF is mentioned as a solution, but availability and cost-efficiency are limited. How realistic is a transition to SAF in the next 5–10 years, and what incentives are needed?

  5. Regulatory Gap: The text mentions that kerosene is "among the few fuels in transportation" for which strict sulfur limit values do not apply. Why do these standards not exist, and who is blocking their introduction?

  6. City Comparability: The study compares airport particle numbers with urban values, but particle mass is lower at the airport. How should one weight number versus mass in health assessment?

Sources

Primary Source:

Tinorua, Sarah et al. – Ubiquity of Aviation Ultrafine Particles and Lubrication Oil Compounds near Zurich Airport – Environmental Science & Technology, 23.04.2026 – DOI: 10.1021/acs.est.5c18458

Supplementary Source:

Paul Scherrer Institute PSI Press Release

Verification Status: ✓ 23.04.2026

This text was created with the support of an AI model. Editorial Responsibility: clarus.news | Fact-Check: 23.04.2026