NO2 monthly product for air quality in South America

ABSTRACT

Air quality is assessed by determining criteria pollutant levels in the atmosphere. While the most significant measurements are ground based, satellite remote sensing is rising as a complementary technique to reveal spatial distribution of pollutants in the integrated tropospheric column. In this work we present a new CONAE's value-added monthly product of nitrogen dioxide (NO2) for South America, derived from the tropospheric NO2 column density estimated by TROPOMI/Sentinel5p (ESA) data. Dataset generation of monthly mean, median, standard deviation and quantity of data used per pixel, along with distribution formats of downloading and visualizing data, are explained in order to provide to different users their characteristics and access. In addition, a spatial and temporal analysis is made for the Buenos Aires, Santiago and Sao Paulo cities along with ground measurements, for the august 2018 to may 2021 period and on a monthly basis. For this matter, higher values of nitrogen dioxide were observed in wintertime for the three cities, due to a greater quantity of stagnation episodes. While satellite derived data follows the temporal profile of ground-based concentrations, Santiago was the city of higher levels and bigger contrast to the summer levels. COVID-19 pandemic restrictions to traffic circulation is also noticed in the diminishing of NO2 in the two datasets, as it was also reported in previous studies. The publication of this new dataset holds the objective of supporting air quality monitoring in South America, helping non specialized users to freely access to interoperational data.