SOURCE FFR - UFP-Belastungsstudie UFP-Immissionsmessungen

Abstract

The exposure study SOURCE FFR measurements · modelling on ultrafine particles (UFP) in the Rhine-Main area was launched on April 1, 2023, with a current duration of 42 months. This study includes the determination of UFP emissions (work package (WP) 1), the determination of UFP immissions (WP2) as input or validation values for a dispersion model, and the determination of the spatiotemporal UFP distribution in the study area (WP3) using dispersion modelling. This report on WP2 describes all the work carried out to obtain particle immission measurement data in the study area. To this end, own measurements were carried out in the Frankfurt area and existing data from third-party providers, such as the Hessian Agency for Nature Conservation, Environment and Geology (HLNUG), were used. In SOURCE FFR measurements · modelling, a dispersion model is being applied to determine the exposure of the population to UFPs for the two years 2019 and 2024. For 2019, only data from HLNUG are available in the form of the number distribution of all particles at four measurement sites for comparing the model results with measured particle immissions. In 2024, measurements were carried out by the consortium in addition, so that measurement data are available for this year at ten measurement sites over periods ranging from three weeks to eleven months. The consortium served a maximum of three measurement sites simultaneously. In addition to the number size distribution of all particles, the data for 2024 also include the number size distribution of non-volatile particles and soot mass concentrations. Furthermore, a total of 220 UFP samples were collected at five measurement sites and subsequently analysed in the laboratory for jet engine oils, sulphate, nitrate, and polycyclic aromatic hydrocarbons. Mobile particle number concentration measurements around Frankfurt Airport, vertical particle measurements with the ALADINA flight system, and particle sample collections east and west of Frankfurt Airport to determine the shape (morphology) of the collected particles supplement the data collected at the fixed measurement sites. In order to assess the extent to which the results of the dispersion modelling correspond to the particle measurements, it is essential to adequately consider the measurement uncertainties. These uncertainties were determined for all particle parameters and are discussed in detail in this report. The most important comparative parameters in the study are provided by the SMPS measurements, which supply both the particle number size distribution of all particles and that of non-volatile particles with diameters in the range of 10-800 nm (10-9 m). The average number size distributions of all particles differ from measurement site to measurement site, with wind direction and the associated proximity to particle sources having the greatest influence on the values. The number concentration of very small particles (10–20 nm in diameter, N10–20) at Frankfurt Airport (in the A-Hof) is approximately 30 times higher than in the urban background. The former values are roughly a factor of 10 higher than the comparative values recorded on a busy road (Friedberger Landstraße). These differences are due to the aircraft’s main engines being the dominant source of 10 to 20 nm particles. Above a diameter of approximately 200 nm, however, the particle number concentrations at different locations differ little; the regional background concentration predominates. Using the ratio of two size fractions (N10-20/N30-50), the exhaust plume from Frankfurt Airport can still be detected at a distance of 15 km, where it contributes on average approximately 10% to the total UFP concentration. In contrast to the UFP number concentration, Frankfurt Airport is not a source of regional significance for the soot mass concentration. For this parameter, the contribution from motor vehicle traffic is greater. Jet engine oils were detected in UFPs at all five sampling locations. This shows that, similar to the number concentration measurements, the exhaust plume from Frankfurt Airport can also be detected by this parameter at a distance of approximately 15 km from the airport. The dilution of the air with increasing distance from the airport is also clearly visible in the jet engine oils (e.g., a factor of 60 from the airport apron to Riedberg site). The results show that the concentration of jet engine oils in UFPs is not significantly influenced by the season. However, for the analysed constituents sulphate, nitrate, and polycyclic aromatic hydrocarbons, the latter as typical combustion markers, no dominant influence of Frankfurt Airport on the region can be determined from the measurements. In addition to data from our own measurements and data from HLNUG, further particle measurement data (number concentrations) obtained by the Federal Environment Agency (UBA), the Max Planck Institute for Chemistry (MPI C) or TROPOS within the framework of the European research infrastructure IAGOS CARIBIC were evaluated. Like own measurement data, these data are used either as input or as validation data for the dispersion modelling. The results of the comparison between measurements and modelling, as well as the actual model results, will then be summarized in the upcoming WP3 report “UFP Immission Modelling” by summer 2026, peer-reviewed and presented in autumn 2026.