Winter and Summer Field Campaings in Hot Spots in Madrid (Spain): Influence of Turbulence on Urban Air Quality

Air pollution is a major problem in the city of Madrid (Spain) during weak synoptic forcing, since the presence of atmospheric stability conditions often gives rise to surface-based thermal inversions during night-time and subsidence inversions during daytime for several consecutive days. TECNAIRE project (Innovative technologies for the assessment and improvement of urban air quality: Ref. P2013/MAE-2972), funded by Madrid Regional Research Plan, has developed different field campaigns during the last years in two of the main hot spots in the city of Madrid (Spain). Both winter and summer extensive field campaigns were carried out in the surrounding of Fernández Ladreda square in 2015, which is representative of the traffic stations outside M-30: the main inner ring-road of Madrid. Along 2016 (summer) and 2017 (winter), two other field campaigns were performed nearby another traffic station, this time inside M-30, with the particularity of being in front of the main park of the city (Retiro park). Turbulent parameters such as sensible heat flux and turbulent kinetic energy, together with other standard meteorological variables, as well as traffic flow in the surroundings, are analysed in order to determine the key parameters responsible for maxima pollutant concentrations, and the differences between summer and winter seasons. In addition, the different turbulent scales present during these episodes with high levels of pollutants are evaluated from Multi-Resolution Flux Decomposition (MRFD) techniques.