Contrasting pollution levels in Île-de-France train stations and stations

Following the first assessment of air quality carried out on 44 station platforms, published in January 2024 [“First reference mapping of air quality on railway platforms”. Airparif (2024) [link], Airparif publishes a complete map of all the platforms of train stations and underground stations in the Île-de-France region. This new map aims to help Île-de-France Mobilités and operators to prioritize their actions in order to improve the air quality in these enclosed spaces with regard to the reference values ​​recommended by the National Agency for Food, Environmental and Occupational Health Safety (ANSES). It also aims to inform travelers about their exposure to particles in each station and station.

On the 426 train platforms and stations reported, the distribution of particle pollution levels, with regard to the reference values ​​recommended by ANSES, is as follows:

•    13 train platforms and stations with high levels of particle pollution,
•    276 train platforms and stations with average particulate pollution levels,
•    123 train platforms and stations with low levels of particle pollution,
• 14 station platforms and stations could not be classified due to lack of information.

The interactive map of the results on the Île-de-France Mobilités rail network, station by station, can be viewed on the Airparif and Île-de-France Mobilités websites [link]

The station platforms leading to the highest exposures to particle pollution are located on lines 2, 5 and 9 of the Paris metro: Belleville (L2), Jena (L9), Jaurès (L5), Laumière (L5), Michel-Ange - Auteuil (L9), Michel-Ange - Molitor (L9), Oberkampf (L5 and L9), Ourcq (L5), Père-Lachaise (L2), Pigalle (L2), Saint-Philippe-du-Roule (L9) and Trocadéro (L9).

An innovative model for assessing air quality

This mapping of exposure to particles in underground railway enclosures is a first. It is based on a statistical model based on an advanced machine learning technique developed by Airparif, capable of estimating the situation in terms of particle pollution with regard to ANSES values ​​on the platforms of each station. This model uses measurement campaigns carried out over long periods by the operators (RATP and SNCF) using reference devices in 44 station platforms, while taking into account 19 factors influencing air pollution in these spaces.

Apart from the frequency of traffic and the configuration of the station (volume, length of tunnels on either side, depth of the station, number of connections and number of entrances/exits of the station, etc.), one of the important lessons of the study carried out by Airparif is that the type of rolling stock, and in particular braking, has a major influence on air pollution levels. Ventilation and the presence of platform doors are also significant influencing parameters.

Recommendations to strengthen surveillance

Airparif recommends continuing the efforts undertaken to improve the monitoring of air quality in underground railway enclosures. In this regard, Airparif recommends carrying out measurement campaigns with reference analyzers on the platforms of stations and stations with high pollution levels, measurements in stations and stations that have recently undergone infrastructure or rolling stock modifications to assess their impact on air quality, and also measurements on lines on which no measurement campaign using a reference analyzer has been carried out. These new measurement campaigns, as well as the integration of additional influencing factors, will contribute to updating the mapping and monitoring the evolution of air quality in underground railway enclosures in Île-de-France, taking into account in particular the action plans implemented by Île-de-France Mobilités and the operators.

Access the interactive map: [link]
Note to decision-makers: Mapping of particle levels on platforms of underground stations and stations in the Paris region. Airparif (2024) [link]