From time to time, during this COVID19 pandemia,I am checking the images of the Copernicus Sentinel-5P, satellite of ESA , which is watching, among others, the concentration of particular pollutants in the earth atmosphere.
The effect of the lockdown orders on the polluting levels in the applied countries is amazing, or at least it is so regarding concentrations of Nitrogen Dioxide (NO2).
Below this lines you can see a short gif showing the NO2 concentration of Spain and Portugal on March 2019 and 2020
Similar situation for France:
Worth to say that The 2.5 micron suspended particles generated by nitrogen dioxide, cause heart problems, kidney disease, Ictus and cancer and it is directly responsible of hundreds of thousands of premature deaths only in Europe.
Perhaps, also with this COVID19 problem, we may say "Every cloud has a silver lining"