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.
Using the SQUALES (Surveillance of Air Quality in Underground Environments) network, our laboratory conducts continuous measurements in premises that are representative of RATP’s underground spaces: two metro stations, at Franklin D. Roosevelt (line M1) and Châtelet (line M4), and one RER station, at Auber (RER A). We measure standard climatic parameters (temperature, relative humidity) as well as air renewal (carbon dioxide) and air quality (nitrogen oxide, particulate matter).
Our verdict? Thermohygrometric conditions are satisfactory, but there is room for improvement
Our observations reveal a warm and dry underground environment, with good air renewal (4 to 40 air renewal cycles per hour) and a limited presence of nitrogen oxide from outdoor pollution.
Yet we did observe high levels of metallic particles (PM10, particulate matter with a diameter of less than 10 µm), emitted primarily by our rolling stock’s historic mechanical braking systems.
Also worth reading
What about other rail networks?
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.