Concentrations of fine particles are three times higher in the metro than in urban air. This is the observation made by the National Health Security Agency (Anses) in an opinion published on Wednesday June 8 that franceinfo was able to consult. Seven years after its first opinion, the Agency confirms “the need to continue actions to limit user exposure, by reducing the concentrations of particles suspended in the air.”
ANSES’s work concerns the metros of the six major urban areas, Paris and its suburbs, Lyon, Marseille, Lille, Toulouse, Rennes, and to a lesser extent Rouen, which has a tram running partly underground. These “underground railway enclosures” welcome several million passengers every day, including around five million for the Ile-de-France network.
The composition of the fine particles measured in these chambers is different from that measured in urban areas, with “a high content of metallic elements, including iron in particular, and also of elemental and organic carbon”, says ANSES. Exposure to these particles has cardio-respiratory effects on health, without it being possible today to determine precisely the consequences.
According to this opinion, “the body of studies remains too limited to be able to draw firm conclusions”. But the Agency stresses that the epidemiological and toxicological data “suggest the possibility of cardio-respiratory effects, inflammation and oxidative stress, and effects on autonomic cardiac function.”
In its opinion, ANSES stresses the need to reduce particulate pollution in metros and calls for continuing actions such as the renewal of rolling stock, the use of braking systems with less particle emissions and the improvement of ventilation of these enclosures.
The Agency is also advocating for the establishment of indicators “allowing to characterize the air quality in these environments”. The calculation of these indicators must include “the exposures over a day in different environments (at home, at work and in transport) and the regulatory limit values, in daily concentrations, not to be exceeded.”
Faced with the expected increase in rail traffic, in a context where alternatives to the car must be given priority, ANSES recommends in particular “to strengthen the air pollution monitoring devices in the different environments of the enclosures: platforms, stations, trains.”
She also pleads for “Improved knowledge of health effects”. Reducing air pollution, especially in urban areasconstitutes “a public health priority”adds the Agency.