Prof. Dr. techn. Günter Scheffknecht Institute of Combustion and Power Plant Technology (IFK) Pfaffenwaldring 23, 70569 Stuttgart, Germany www.ifk.uni-stuttgart.de Study area With 12.7 million passengers (2019) and around 400 flights per day, Stuttgart airport is the 6th largest airport in Germany. The investigations were carried out in three phases in 2020. The measuring locations were on both sides of the airport, at different distances in a direct extension of the runway. The results presented here focus on locations west of the runway at 1 km (Point 2) and 2 km (Point 1) from the start of the runway. The planes were approaching from the west with easterly winds. In addition, measurements were carried out on a bridge over the busy federal highway B27. Contribution of Airplane Engine Emissions on the Local Air Quality around Stuttgart Airport during and after COVID-19 Lockdown Measures Aim of the study Previous airport studies conducted in Los Angeles, Amsterdam and other cities have shown that aircraft can significantly increase air pollutant concentrations around the airport and can be measured even at distances of several kilometers. Since the results cannot be directly transferred from one city to another and no comparable measurements were carried out at Stuttgart airport, the aim of the study was to investigate whether increased air pollution levels can be measured at the airport fence and in the immediate vicinity of the airport in Stuttgart. Since there are busy roads in the immediate vicinity of the airport (e.g. A8, B27), it should also be investigated whether the exhaust gas plumes from road traffic and air traffic can be distinguished. Methodology The vehicle platform, a Renault Twizy, was equipped with the following measurement technology. The runway at Stuttgart airport was renovated at the beginning of the COVID-19 pandemic in April 2020. The airport was therefore closed (Measurement phase I - mid April 2020). The airport was then reopened but due to the COVID-19 lockdown measures, very few flights took place (Measurement phase II - early to mid June 2022). More flights took place during the 2020 summer holidays, but still the number of flights were around 50% fewer than before the COVID-19 pandemic (Measurement phase III - mid August to mid September 2020). Conclusions Landing planes produced increased concentrations of very fine particles. The mean diameter of the measured particles drops to very low values of 10 to 20 nm. Peaks were easily measurable even at a distance of 2 km. Road traffic emissions also produced UFP, but with slightly larger diameters. Hence, UFP can be distinguished from road and air traffic. Outlook Mobile measurements should be carried out in adjacent residential areas, also at a greater distance from the airport. Mobile measurements in combination with long-term measurements should provide information about the exposure of the population to high pollutant concentrations in the vicinity of the airport. More information regarding this research can be found in the following publication: Samad, A.; Arango, K.; Chourdakis, I.; Vogt, U. Contribution of Airplane Engine Emissions on the Local Air Quality Around Stuttgart Airport During and After COVID-19 Lockdown Measures. Atmosphere 2022, 13, 2062. DOI: https://doi.org/10.3390/atmos13122062 Contact: M.Sc. Abdul Samad – abdul.samad@ifk.uni-stuttgart.de Department of Flue Gas Cleaning and Air Quality Control (RuL) Results Measurement phase I - no air traffic: The PNC concentrations were at a low level with values < 10,000 particles/cm³, the mean particle diameter Dp at > 40 nm. Measurement phase II – less air traffic: Individual peaks from landing aircraft could be recorded. PNC concentrations were > 10,000 particles/cm³ at recorded aircraft peaks. Measurement phase III – substantial air traffic: Many UFP peaks from landing aircraft could be recorded. They generated PNC peaks of up to 300,000 particles/cm³. During the PNC peaks, the average pa