As if the high number of deaths linked to Covid-19 worldwide were not enough, a study coordinated by Harvard University, with three British universities (in London, Leicester and Birmingham), indicates that 8.7 million premature deaths are to be deplored in 2018, in connection with the combustion of fossil fuels.
It is published in Environmental Research, February 9.
This is more than double the most pessimistic previous estimates which predicted 4.2 million premature deaths per year worldwide.
For France alone, the number of premature deaths is estimated at nearly 100,000 (97,242), which would represent 17% of deaths recorded in 2018. While traditional studies carried out in Europe, estimate this level at around 48,000 premature deaths per year in France, because of fine particles of the PM2.5 type (which are less than 2.5 micrometers in diameter).
However, even smaller particles can enter deep into the lungs, pass into the bloodstream and create chronic inflammation, heart problems and even cancer.
These mechanisms have been refined in recent years, in particular due to measurements of even smaller particles (PM1) which could even be found in the brain.
The originality of the latest publication is to focus only on particles (PM2.5) resulting from the combustion of fossil fuels and to study their dispersions with a geochemical simulation model on the scale of the planet.
They are therefore no longer based on local measurements and satellite images.
Because
"with satellite data, you only see pieces of the puzzle,"
said Loretta J. Mickley, researcher in chemistry-climate interactions at the John Paulson School of Engineering and Applied Sciences at Harvard in a statement.
It would then be
"difficult to distinguish between different types of particles, and there could be data gaps
.
"
Significant drop in China
Researchers estimate that globally,
“exposure to particulate matter from fossil fuel emissions accounted for 21.5% of the total number of premature deaths in 2012, falling to 18% in 2018 thanks to the strengthening of quality measurements of air in China ”
.
The number of premature deaths remains high, estimated at 2.4 million, but it is now behind India (2.5 million), due to a 43.7% decrease in PM2.5 emissions from of fossil fuels from 2012 to 2018 in China, the publication says.
In addition, other families of fine particles present in cities and more harmful than rural aerosols could further darken the picture.
In an article published in November 2020 in Nature, researchers from the CNRS, IRD and the Paul Scherrer Institute (PSI) in Lausanne focused on these “oxidizing” particles, which are more harmful to health. .
“These particles are the soot associated with the combustion of wood and metal particles produced by the braking of vehicles,”
explains Gaëlle Uzu, IRD research director at the Institute of Environmental Geosciences.
These particles are harmful to health and have an inflammatory character on lung cell lines ”
.
The researchers not only measured these particles, demonstrated their harmful effects, but they
"redrawn a map of Europe, to take into account these fine oxidizing particles, which are rather very present in all the large cities and European industrial zones"
.
And like the Harvard researchers, they used modeling tools to assess the dispersion of these particles.
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