Estimating surface-level NO2 concentrations in the Madrid region using Sentinel-5P observations and ground-based meteorological data with machine learning approaches - Morillas, Carlos; Giosa, Rocco; Alvarez, Sergio; Serio, Carmine; Masiello, Guido; Liuzzi, Giuliano; Aviles, Carmen; Martinez, Sara (ATMOSPHERIC ENVIRONMENT, 2026)