This is not new, but it is no less worrying. For several years, the air quality in metro and RER stations in the Paris region has been singled out. Last April, an investigation was even opened on this subject against the RATP. . Presented this Tuesday at the Climate Academy, a new study draws up a map of this pollution on the scale of the Ile-de-France network.
For eight months, the show’s investigative journalists Green of Rage, broadcast on France 5, measured the concentration of PM2.5 particles on the 435 platforms of the 332 stations in transport zones 1 and 2 in the region. “Samples taken from 6 p.m. to 8 p.m., Monday to Friday,” the report said.
The average concentration of fine particles twice the WHO recommendations
These PM2.5 (whose diameter is less than 2.5 microns (μm)) have the particularity of being able to infiltrate our lungs, and some can go as far as the pulmonary alveoli. Chronic exposure contributes to increasing the risk of contracting cardiovascular and respiratory diseases, as well as lung cancers. According to a study by the Regional Health Observatory (ORS) Ile-de-France and Airparif, 6,220 deaths were “attributable to prolonged exposure to fine particles PM2.5” in 2019 in Ile-de-France.
And the figures revealed by Vert de Rage are not reassuring. On average, the excess pollution caused by metro and RER traffic amounts to 10.5 μg/m3, which is “twice as much (5 μg/m3) as the recommendations of the World Health Organization ( WHO)”, warns the report. But these measurements do not show homogeneous results. For example, line 5 is the one that showed the average overpollution “the greatest in the network with 18 μg/m3, “that is 3.6 times higher than the WHO recommendations”.
In total, of the 21 lines in the network, 14 greatly exceed the WHO recommendation level, two are at the recommended limit level and five lines are below the reference (see table).
To go further and know more about the pollution found in the network, the initiators tackled the composition of the polluted air. With the help of the toxicologist of the toxicology laboratory of the Lariboisière Hospital, Joël Poupon, they deployed a new study in order to measure the levels of heavy metals. Thus, 55 people, including 43 travelers and 12 volunteer drivers, were fitted with a nose filter on their usual route.
An iron concentration up to 20 times that measured in the open air
For users, it was a question of wearing this small device for thirty-six minutes to go and 36 minutes to return, “that is the average duration of home-work journeys” explains Martin Boudot, journalist for Vert de Rage. At the same time, other volunteers made journeys of equivalent duration in the open air, by bicycle or on foot, to serve as control values.
And the conclusion of the report is clear: “On average, the levels of heavy metals inhaled by RATP users are all higher than those inhaled by people who have not taken the metro and RER. And not just a little, up to 20 times higher than those of the control values for iron, 17 times for manganese. “On average, users have manganese levels 2.6 times higher than the toxicological reference value for respiratory exposure proposed by the US Environmental Protection Agency (EPA). »
This pollution, caused by the abrasion of the metal brakes of the trains, the rubber wheels of certain trains or even the mineral environment of the tunnels, is added to the external pollution which enters the corridors through the vents of ‘aeration.
“It is urgent that the public authorities and the manager take up this problem”
“We also carried out air measurements outside the stations to find out the level of pollution in the ambient air of Paris. This allows us to be able to measure the difference between the inside and the outside of the stations and thus to only measure the “over-pollution” generated by the RATP metros and RERs”, explains Martin Boudot, journalist at the origin of the ‘study.
“This study shows the seriousness of the air quality situation in the underground transport network managed by the RATP. It is urgent that the public authorities and the manager of this network take up this problem in order to reduce particle emissions and the exposure of users”, comments Jean-Baptiste Renard, member of the scientific committee of the RESPIRE association and director of research at the CNRS, which analyzed the results for the Vert de Rage team.
The RATP defends itself
Contacted by 20 minutesthe transport authority retorts by highlighting an interview with Matteo Redaelli, air quality specialist at the National Health Security Agency (Anses), who responded to previous studies, on May 13 in the Parigo show “What emerges overall from these studies is that it does not highlight any harmful effects on pathologies, therefore an exacerbation of pathologies or the incidence of a pathology in users who would be exposed to the air of the metro. »
But to the next question, the researcher added “what we know is that there is no increased risk of myocardial infarction or risk of lung cancer in these workers” before specifying that there were “very few studies”.
In addition, the RATP is advancing a report from Airparifpublished in July 2022, which evaluated the “air quality monitoring and information system in the underground stations where the RATP operates for Île-de-France Mobilités” validated by the French Accreditation Committee (COFRAC ) as “the most comprehensive in the world” since it continuously measures PM10 particles, PM2.5 fine particles, nitrogen oxides (NOX) and carbon dioxide (CO2).
New solutions
“The RATP works in complete transparency with measurement systems, the data of which is permanently available on our Ratp.fr website. We are also working to reduce particle emissions at source with the deployment of electric braking on all new equipment, already effective on lines 2, 5, 9 and 14 of the metro. In the short term, lines 4, 14 and 11 of the metro will benefit from it, followed by all the lines of the Paris metro. »
To complete this solution, brake linings, “significantly limiting fine particle emissions, are being tested on the RER A (3 trains equipped for one year and then 10 soon), with Faiveley Wabtec”.
RATP also launched a study in 2018 with the Lausanne Health Institute (Switzerland), to analyze the effects of air quality on agents exposed to 300 employees, the results of which should be known in the second half of 2023. .
“Our job is not to hit the RATP for free. Moreover, our measurements are very very close to those made by their instruments. Proof of their reliability. The idea is to shed light on this problem, which in our view is too little considered by the RATP, which has only two measuring instruments (in the Auber and Nation stations), and to carry out a real study to encourage them to study the solutions that exist and to establish a non-existent legal framework”, concludes Jean-Baptiste Renard.