Is the air of the Paris metro more or less polluted than that of the surface? According to readings taken over several months by volunteers on behalf of the France Télévisions program, “Vert de rage”fine particle pollution in the Paris metro and RER reaches values well beyond the standards recommended by the World Health Organization (WHO).
For eight months, dozens of these volunteers equipped themselves with measuring tools during their daily journeys in order to establish the level of pollution on the RATP network, and compare it to that of the outside air. This pollution with fine particles comes both from the polluted air of the streets, which ventilates the stations, and from the metro trains themselves, which create dust during braking.
On average, PM2.5 fine particle pollution (diameter less than 2.5 micrometers) in the metro and RER is 24 micrograms per cubic meter (μg/m3), i.e. almost five times more than the 5 μg/ m3 recommended by the WHO, details in a press release Monday “Vert de rage”, a program broadcast on France 5 which investigates environmental scandals. Over-pollution, defined as excess pollution inside the station compared to outside, was measured at 10.5 μg/m3 on average.
Several studies carried out in recent years
The study was coordinated by Jean-Baptiste Renard, director of research at the National Center for Scientific Research (CNRS) and member of the scientific committee of the association Respire, at the origin of a complaint which led in April to the opening of an investigation targeting the RATP for “endangering others and deceiving”. This work has not been published in a scientific journal, but is in addition to others carried out using various methods over the years.
A year ago, the National Health Security Agency (Anses) estimated that “the body of specific epidemiological and toxicological studies [était] too limited to be able to draw firm conclusions on the possible health effects of the exposure of users to air pollution”but noted that existing data suggested ” the possibility “ cardio-respiratory effects.
“Such measurements must be carried out according to validated scientific protocols and with reference material”reacted to Agence France-Presse the RATP by the voice of its head of the sustainable development department, Sophie Mazoué, questioning the method and the devices used by the study of “Vert de rage”.
The RATP says it is putting in place measures, such as air renewal devices and brake linings to reduce the risks. Proof of the actions carried out and their effectiveness: an epidemiological study carried out over the period 1980-2017 which “does not show an increase in respiratory and cardiovascular symptoms among our employees”insists the Régie.
The study carried out by “Vert de rage” established a ranking of the most polluted stations and lines, with line 5 at the top, “where the average pollution caused by traffic” is 18 μg/m3, followed by line A of the RER and line 9 of the metro.