Impact of turbulence and meteorological conditions on air quality in Madrid (Spain) analysed through field measurement campaigns

In-situ measurements in cities are crucial for studying the physical processes that occur within them, which impact on key aspects such as the increased temperatures in the city centre compared to their rural surroundings, as well as air quality. It is widely known that meteorology plays a significant role in the daily fluctuations of pollutants, especially those variables related to atmospheric dispersion. Furthermore, these measurements are essential for the accurate evaluation of numerical simulations carried out in urban environments.

This work will present data from four intensive measurement field campaigns carried out in Madrid, Spain, during the years 2020 and 2021, both in winter and summer, near two public buildings (a university and a hospital). The results obtained from various instruments will be provided, offering a comprehensive analysis of the meteorological conditions observed during the campaigns, including both synoptic and local factors. The specific meteorological conditions of each campaign were linked to the pollutant concentrations observed in the area. Additionally, turbulent measurements obtained from sonic anemometers installed at different locations will be considered.

In this sense, the winter 2020 field campaign included a particularly stable period during which turbulence typically decreased in the evening, leading to the highest observed NO₂ concentrations during the four field campaigns. However, under these stable conditions, thermally-driven winds were also observed later at night, enhancing pollutant dispersion and leading to a reduction in pollutants concentration. The interaction between turbulence and pollutant levels will be further analysed, focusing on the role of the different dynamic processes in the evolution of NO₂ concentrations. Understanding these interactions is essential for improving urban air quality and assessing the impact of meteorological factors on pollution dynamics.