Caring about air quality in our spaces

Our monitoring is geared primarily towards ensuring that we respect sanitation and cleanliness standards in our spaces, those used by passengers as well as those used by our employees.

Thus, with the support of Île-de-France Mobilités, we have been conducting continuous measurements since 1997, year-round and 24/7. These measurements currently cover five stations: Franklin D. Roosevelt (line 1), Châtelet (line 4), Gare d'Auber, Nation, and Châtelet-les-Halles (RER A), using reference devices. These five stations are among the most heavily frequented areas in Île-de-France. Continuous measurements are available on the dedicated ratp.fr website, and a QR code in the stations will soon enhance accessibility to this information for passengers. Additionally, periodic measurements are regularly carried out throughout the entire network.

For over 25 years, RATP has been engaged in a monitoring, surveillance, and expertise activity related to the air quality within the underground network in collaboration with Île-de-France Mobilités (IDFM), ANSES, Inéris, and Airparif.

Airparif, a recognized authority on air quality, published an evaluation report in July 2022 regarding the air quality monitoring and information system in the underground stations operated by RATP for Île-de-France Mobilités. In its report, Airparif highlights that the air quality measurement system implemented by RATP for Île-de-France Mobilités over the past 25 years is "the most comprehensive in the world." This is particularly noteworthy because it encompasses monitoring of various air quality parameters, including PM10 particles, fine PM2.5 particles, nitrogen oxides (NOX), and carbon dioxide (CO2). Furthermore, according to an international comparison conducted by Airparif, the RATP-operated network ranks in the top 5 for the least polluted transport networks in terms of PM2.5 and PM10 levels.

It's important to note that, as of now, there are no legal or regulatory standards in place for evaluating air quality in underground railway premises. However, in 2022, ANSES (the French Agency for Food, Environmental and Occupational Health & Safety) published general recommendations, which RATP endeavors to follow, taking into consideration the exposure time of passengers.

Beyond monitoring air quality on its network, RATP's action plan for improving air quality relies on various strategies:

• Strengthening and modernizing the station ventilation system to enhance indoor air renewal. A substantial investment plan of €57 million, funded by Île-de-France Mobilités, has already been initiated for the period 2021-2024.
• Implementing regenerative braking on new trains and testing new materials for mechanical braking.
• Gradually phasing out thermal engines in maintenance operations.
• Experimenting with multiple technological solutions to improve air treatment at stations, including filtration, particle fixation, and capture solutions.
• Conducting epidemiological studies regarding the exposure of RATP employees to air quality conditions.

We exchange information on air quality issues with foreign rail networks (Stockholm, London, etc.) via the International Association of Public Transport (UITP).

A summary of research work conducted on other French rail networks (Lyon, Toulouse, Rennes and Lille) shows that air quality is similar to that measured in Paris. In Toulouse and Lyon, the hourly maximum value of PM10 ranges between 200 and 500 µg/m³. In London, punctual measurements point to values ranging between 500 and 1,120 µg/m³.