Properties and Chemistry of Ultrafine Particles at Zurich Airport

Zachary Decker, Peter A. Alpert, Jay G. Slowik, Michael Bauer, Markus Ammann, Lukas Durdina, Jacinta Edebeli, Curdin Spirig, André S. H. Prévôt, Julien Anet, Martin Gysel, BENJAMIN BREM, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute

     Abstract Number: 632
     Working Group: Combustion

Abstract
Aviation emission impacts on ground-level Ultra Fine Particle (UFP) number concentrations have been identified to be significant over extensive areas near airports and along flight paths under certain meteorological conditions. For example, significantly elevated PN concentrations were reported as far as 7 km and 22 km downwind of the Amsterdam Schiphol and London Heathrow airports, respectively . A rapid evolution of aerosol properties within the fresh aircraft engine plume takes place involving coagulation as well as nucleation and condensation of semi volatile species. Therefore, an assessment of aviation emission air quality impacts requires not only a detailed understanding of the emissions at the engine exit plane, but also a comprehensive and mechanistic understanding of the evolving chemical and physical processes in the plume.

As part of the Aviation Plume PROPeRtIes AT point of Exposure (APPROPRIATE) research campaign, we carried out laboratory, engine test site, and airport ambient field measurements with a comprehensive suite of physical and chemical gas- and aerosol-phase instrumentation. The chemical measurements included VOCUS Proton Transfer Reaction Time of Flight Mass Spectrometry (VOCUS PTR-ToF-MS), Extractive Electrospray Size Selected Ionization ToF-MS (EESSSI-ToF-MS) and an Aerosol MS (AMS).

We will show that field results confirm the utility of the chemical tracers identified in our laboratory studies. Interestingly, markers for fresh oil were not detected, even in newly overhauled engines, suggesting aircraft oil emissions undergo significant chemical change after first use. In contrast, chemical markers of used oil and commonly known oil components (e.g. tricresyl phosphate) were detected at both the test cell and field site. Ambient measurements detected several individual aircraft UFP plumes and many oil markers and we will discuss the efforts to quantify them in the context of airport operations.