Among the top 5 unpleasant odors of everyday life, that of the metro figures prominently.

The explanation may come from the composition of the air in our underground transport.

According to a study by the National Health Security Agency (Anses), the level of fine particles is “on average three times higher than in urban outdoor air”.

The fault of the wheels rubbing on the tracks during braking, which tears off iron, and the dust resuspended with each passage of the oar.

In 2019, ANSES was commissioned by the public authorities to carry out a study on the feasibility of developing "guide values ​​for indoor air" in "underground railway enclosures".

Seven cities in France have underground networks: Lille, Lyon, Marseille, Paris, Rennes, Rouen and Toulouse.

But the available data are insufficient, regrets ANSES, because "the corpus of specific epidemiological and toxicological studies is too limited to be able to draw firm conclusions on the possible health effects of the exposure of users to air pollution. air from EFS", despite the "possibility" of cardio-respiratory effects.

Know your exposure according to the route

The agency recommends strengthening air quality measurements in these underground networks, which are not yet widespread.

And thus to be able to set up air quality "indicators", determined in particular according to the respective durations of journeys on the different networks and which "integrate exposures over a day in different environments - at home, at work and in transportation.

The accumulation of these particle concentrations should comply with the exposure standards set by a 2008 European directive on air quality and if possible those of the WHO, stricter than EU regulations and tightened in 2021 to take into account account the most recent knowledge on the health impact of air pollution.

The available measurements suggest that European regulations are “generally respected,” explains Marion Keirsbulck of ANSES, who stresses that “this is much less the case” for the WHO values.

Targeted by a complaint, the RATP "extremely mobilized"

On the Parisian network “there are only three stations which are well instrumented”, notes Eric Vial, director of risk assessment at ANSES.

And these measurements are carried out by fixed sensors on the platforms, while it would also be necessary to regularly study corridors and trains, underlines the opinion.

The air quality in the Paris metro has already given rise to legal action.

The Respire association filed a complaint against the RATP in March 2021 for "aggravated deception" and "involuntary injuries", questioning the levels of air pollution.

Ile-de-France Mobilités launched an action plan at the end of May to improve air quality in metro and RER stations.

New measurement points are planned, in particular on ultra-fine particles, the results of which will be public like those already practiced.

The RATP “is extremely mobilized” on the subject, betting in particular on “technological improvement” to reduce emissions at the source, insists Sophie Mazoué, responsible for sustainable development at the Parisian board.

Tests have thus been launched in the RER on new brake linings, whose “very promising” preliminary results on the test bench have shown a 90% reduction in particle emissions, explains the manager.

Investments of 57 million euros are also planned for ventilation, with experiments in “electrostatic filtration” stations and “particle trapping systems”.

Planet

Air pollution: The Respire association denounces a problem that "is not sufficiently taken into account"

Paris

Aubervilliers: Warm welcome from users for the two new stations on line 12

  • Health

  • Air pollution

  • Fine particles

  • Subway

  • Air quality

  • Paris

  • RATP

  • Ile-de-France