Health of passengers and local residents

• Monitoring focuses primarily on the hygiene and cleanliness of RATP premises, for the benefit of both staff and passengers. Since 1982, Paris City Council’s hygiene laboratory has measured carbon dioxide levels in the air, an indicator of how well the air is refreshed.
• RATP’s own laboratory conducts continuous measurements in three stations representative of RATP’s underground environments (Châtelet, Franklin D. Roosevelt and Auber). These three stations are collectively known as the SQUALES network. The measurements concern temperature and relative humidity, as well as air renewal (carbon dioxide) and air quality (nitrogen oxides, particles). The SQUALES network automatically generates over 200,000 items of raw data each year.
• Occasional measurement campaigns are used to monitor other parameters, such as ultrafine particles, aldehydes and monocyclic or polycyclic aromatic hydrocarbons.

RATP also takes part in passenger exposure studies on typical routes in the Île-de-France region as part of the Primequal-Predit project in partnership with Paris City Council’s hygiene laboratory and the Laboratoire central de la Préfecture de Police.

The measurements show temperature and humidity conditions to be satisfactory, with:

• A warm, dry underground environment;
• Good air renewal (4 to 40 air changes per hour);
• Low levels of nitrogen oxide from exterior pollution.

However, high levels of metallic particulates have been observed (PM10, particles less than 10 µm in diameter), the majority of them emitted by old trains’ braking systems.

In order to improve air quality, RATP is working to improve ventilation and cleaning. As part of the regional Plan to Protect the Atmosphere, RATP is committed to replacing mechanical braking systems with electric brakes when renewing its metro and RER trains.

…with other rail networks:

RATP engages in dialogue on air quality with rail networks from other countries (Stockholm, London, etc.), via the International Association of Public Transport (UITP). Measurements taken in other French networks (Lyons, Toulouse, Rennes, and Lille) show a comparable air quality to that measured in Paris. In Toulouse and Lyons, the maximum hourly PM10 values are between 200 and 500 µg/m³. In London, occasional measurements have shown levels varying from 500 to 1,120 µg/m³.

…with other enclosed spaces:

Work done by the French Indoor Air Quality Observatory (OQAI) and Airparif on the exposure of people to air pollution in their home or their car can be used to compare exposure levels in different environments.

• The NO2 (nitrogen oxide) levels measured on Paris’s outer ring road, the Boulevard périphérique, on 18 May, 2007, a day on which traffic was free-flowing, were between 110 and 260 µg/m³ inside the car. Outside the car, they varied from 40 to 520 µg/m³.
• On the RATP network, NO2 levels on 18 May, 2007 (at the 3 stations in the SQUALES network) varied from 20 to 90 µg/m³.

In the 290 French homes in which PM10 measurements were taken between 2003 and 2005, levels varied between 2 and 522 µg/m³.

On 4 July, 2008, RATP and the independent association Airparif signed a partnership agreement for a minimum duration of 3 years. The aim is to improve current knowledge about air quality in RATP railway networks, as well as the impact and advantages of public transport in respect of exterior air quality.
Two measurement campaigns were conducted over the period 2008-2009, one at Faidherbe-Chaligny station (line 8), and the other in the passenger hall at Auber station on the RER A. The results of these measurements are available to the public in English on the Airparif website.