Jean-Baptiste Renard is convinced of this. If Paris or Lombardy, in the north of Italy, were very strongly affected at the height of the Covid-19 pandemic, it is because they share an aggravating factor: the poor quality of the air we breathe their inhabitants. “It is the most polluted cities that have experienced the highest mortality rates, notes the expert, research director at the CNRS within the Laboratory of Environmental Physics and Chemistry and of space. Conversely, cities like Bordeaux or Brest, much less polluted due to oceanic influence, have been largely spared. » In a study published at the beginning of August in the journal Science of the Total Environment, in collaboration in particular with Isabella Annesi-Maesano, research director at Inserm and recognized specialist in pollution issues air, Jean-Baptiste Renard highlights a correlation between the level of exposure to fine particles (PM2.5, diameter less than 2.5 micrometers) and mortality due to Covid-19. This link had already been mentioned in several works. The originality of this new publication lies in its ability to quantify the phenomenon.
Based on the case of Paris (the best documented) and extending it to 31 other cities and regions in six Western European countries (France, Germany, Italy, Spain, Netherlands and United Kingdom) over the period 2020-2022, the study shows that the highest mortality levels are observed during pollution peaks and vary depending on their intensity. And in considerable proportions. Based on the analysis of all the data, the researchers managed to identify a trend: an increase in mortality of around a factor of 5 is observed when PM2.5 concentrations flirt with the 45 micrograms per cubic meter. Levels reached in Paris and Lombardy. The authors deduce an increase of approximately 10% in mortality per microgram per cubic meter of additional fine particles.
Full article (Fr) : Le Monde