To assess the best measures for the improvement of air quality, it is crucial to investigate in situ and columnar pollution levels. In this study, ground-based measurements of nitrogen dioxide (NO2) and ozone (O-3) collected in Rome (Italy) between 2017 and 2022 are analyzed. Pandora sun-spectrometers provided the time series of the NO2 vertical column density (VC-NO2), tropospheric column density (TC-NO2), near-surface concentration (SC-NO2), and the O-3 vertical column density (VC-O-3). In situ concentrations of NO2 and O-3 are provided by an urban background air quality station. The results show a clear reduction of NO2 over the years, thanks to the recent ecological transition policies, with marked seasonal variability, observable both by columnar and in situ data. Otherwise, O-3 does not show inter-annual variations, although a clear seasonal cycle is detectable. The results suggest that the variation of in situ O-3 is mainly imputable to photochemical reactions while, in the VC-O-3, it is triggered by the predominant contribution of stratospheric O-3. The outcomes highlight the importance of co-located in situ and columnar measurements in urban environments to investigate physical and chemical processes driving air pollution and to design tailored climate change adaptation strategies.
Di Bernardino, A; Mevi, G; Iannarelli, AM; Falasca, S; Cede, A; Tiefengraber, M; Casadio, S
Temporal Variation of NO2 and O3 in Rome (Italy) from Pandora and In Situ Measurements
Atmosphere