Since the start of the strike against the pension reform on December 5, the roads of Paris and its region have been particularly saturated. On December 6 in particular, in the early evening, 600km of traffic jams, twice the usual average, were recorded in Ile-de-France.
An increase in traffic necessarily means an increase in the release of pollutants, such as sulfur dioxide, nitrogen dioxide, carbon dioxide or fine particles. Despite its traffic jams, however, the strike did not blow up Airparif’s readings.
The association responsible for measuring air quality in the region focused its study on the first fifteen days of the strike, when road traffic was the heaviest. As Charlotte Songeur, engineer at Airparif recalls, “For pollution levels to increase, there must be both a high emission of pollutants, but also that they are not dispersed in the atmosphere according to the weather. When it rains, for example, it leaches out the particles and prevents the spread of secondary pollutants ” which are not emitted directly but form when pollutants react in the atmosphere.
Ile-de-France residents have probably not forgotten: during the first days of the strike, it was in the pouring rain that they had to go to work, often by bicycle or on foot. “During the first fortnight of mobilization, during the morning rush hour, we recorded + 13% of emissions of nitrogen dioxide (Nox) and carbon dioxide (CO2). Ditto for PM10 particles (less than 10 microns) that enter our respiratory system, ” explains Charlotte Songeur. However, we have not exceeded the ‘information threshold’ for particulate matter pollution set at 50 micrograms per cubic meter. “All this thanks to the weather conditions (winds and rains) which were very favorable to air quality and made it possible to mitigate the surplus of pollutants. If the weather was nice, we would have exploded the meter “, She adds.
Respiratory and cardiovascular problems
The engineer reminds, however, that if the air quality was not too bad, the impact on the planet was real because of the peaks of CO2, one of the main greenhouse gases responsible for global warming. climate. In recent days, traffic has gradually subsided but pollution levels have tended to rise. “At this moment, we are approaching the threshold of 50 μg / m3 precisely because of the weather conditions which results in a blockage of pollutants”, notes Charlotte Songeur.
She recalls that Nox are irritating gases which can cause respiratory and cardiovascular problems: “If you are exposed to a concentration of 40μg / m3 every day for a year, Nox can become dangerous for your health. In 2018, at least one million Ile-de-France residents were in this case ”. Fine particles from wood heating, diesel engines and industry can also worsen chronic conditions like asthma. In the long term, they can promote the appearance of cancers or cardiovascular problems.