This is one of the positive consequences of confinement: thanks to the drastic reduction in automobile traffic, the atmosphere is today much more breathable. The measurement agency Airparif noted "an improvement in air quality of the order of 20 to 30% in the Paris conurbation, following a drop in emissions of more than 60% for nitrogen oxides During the week of March 16-20. Unheard of in forty years! Air pollution specialists, however, have a problem. If we look at the data in detail concerning fine particles, the improvement was not as visible as Airparif recognizes that they "come from more sources".
In fact, "the decrease in traffic did not compensate for the increase linked to residential heating and the maintenance of agricultural activities, combined with a spring weather favorable to the formation of particles observed in several neighboring regions" underlines the public body. "Each year in the spring, there is a peak in pollution linked to the resumption of agricultural activities, especially spreading," said the president of the Respire association, Olivier Blond. Is there a greater risk of contracting the coronavirus when living in a city where the air is stale? To believe some doctors, the link is quite obvious.
"There are more respiratory problems in urban areas exposed to pollution, which can therefore expose the most fragile subjects more to viruses," says Isabella Annesi-Maesano, epidemiologist at Inserm (national institute of health and medical research). "Pollution has pro-inflammatory effects and fine particles can not only transport heavy metals, pollens but also undoubtedly viruses and therefore alter the immune and respiratory defenses of exposed people", underlines the pulmonologist Brunot Housset.
Air quality associations are driving the point home. “Numerous studies have shown a relationship between air pollution and hospital admissions for respiratory diseases, as well as an increase in morbidity (note: the number of new cases) and mortality from various respiratory diseases , explains Olivier Blond. The harmful role of air pollution during the SARS epidemic in China in 2002 has been demonstrated after the fact. According to the NGO, "pollution peaks in certain regions have accelerated and intensified the spread of the virus via susceptible people". And the association Respire to report this retrospective study which showed "the importance of air pollution from coal in the mortality from the influenza pandemic of 1918".
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The European Public Health Alliance (EPHA), an association bringing together doctors, tobacco specialists, patients and air pollution specialists, has just sounded the alarm, believing that people who live in polluted cities have more risk that others face Covid-19. "Air pollution can cause hypertension, diabetes and respiratory problems, conditions which doctors believe may be linked to higher death rates from coronavirus," says EPHA. A 2003 study of victims of the SARS coronavirus showed that patients living in moderately polluted areas were 84% more likely to die than those living in areas with low air pollution. ”
Accelerate the ecological transition
Epidemiologist Isabella Annessi-Maesano believes that pollution could be a “vector for transporting viruses”. "Fine particle pollution damages the mucous membranes and the airways and is also a factor in the aggregation of viruses, bacteria and pollens," explains the researcher. In his eyes, it is no coincidence that the epidemic hit North Italy, very industrial, and Lombardy which is "geographically a basin". But also countries reputed to be very polluted such as China, Iran or South Korea. "Once this crisis is over, public authorities will have to speed up measures to drive the most polluting vehicles off our roads," said EPHA secretary general Sascha Marschang. Because scientists tell us that epidemics like that of Covid-19 will occur more frequently. Cleaning our streets is therefore a basic investment if we want a healthier future. "
