Scientists from the Royal Netherlands Meteorological Institute (Knmi) used the data received from the satellite Copernicus Sentinel-5P to monitor pollution in Europe.
The data obtained are showing a drastic reduction of nitrogen dioxide concentration in several important cities, in particular Milan, Paris and Madrid, coinciding with the rigorous quarantine measures put in place to contain the spread of the Covid-19 coronavirus. As early as mid-February, Copernicus found a 10% weekly reduction in the surface concentrations of NO2 in Northern Italy after the country shutdown. Furthermore, Ispra, the Higher Institute for Environmental Protection and Research, in the first quarter of 2020, due to restrictions on mobility, estimates that CO2 emissions will be at least a 5-7% lower than in the same quarter of 2019.
https://www.ecomobile.it/index.php/en/news/151-ambiente-en/2957-covid-19-emissions-what-the-satellite-is-registering#sigProIdb4c939844c
