Health of passengers and local residents

Since 2007, temperature and relative humidity in the metro network have been constantly monitored in order to detect any changes. 31 stations on all metro lines are equipped with such monitoring systems.

A number of factors and devices contribute to heat generation in underground areas. The amount of heat given off depends on:

• The age of, and technology used in, the rolling stock operating on the line;
• The electro-mechanical equipment;
• The lighting;
• The low-voltage systems (signalling, video-surveillance, transmissions), which are often equipped with forced ventilation systems or air conditioning devices to reduce the temperature;
• The number of passengers in the trains or stations.

The climatic conditions in the metro are highly dependent on the external temperature.

• On average, when the external temperature is 0°C, the temperature in metro stations will be approximately 10 to 15°C.
• In winter, ventilators in the tunnels renew the air and cool the tunnel walls in the stations.
• During the summer, this cooling effect is insufficient. When it is 30°C outside, temperatures in the stations are 2 to 3°C higher, except in some large areas that are easier to ventilate, such as Cour St-Emilion and Madeleine stations on line 14.

The new MF01 trains that are being progressively rolled in on lines 2, 5 and 9, and the new MI2N train on line A of the RER, will bring about a noticeable improvement in passenger comfort. Renovation projects provide an opportunity to address the weaknesses of older areas, equipment and infrastructures.

In the case of rolling stock, actions are focussing on:

• Reducing the temperature to which RERs trains are heated in winter;
• Electronic power modulation and regenerative braking;
• Improving inter-circulation between carriages of the same train (lines 14, 1, 2),
• Heat-absorbing windows on buses (lowering temperatures by approximately 2°C),
• Forced ventilation of buses and trains and air conditioning for overground trains;
• Optimisation of opening panels to allow better air circulation on the MS 61 trains operating on RER line A;
• Establishing green spaces at new overground stations.

The measures being taken with regard to infrastructures and spaces mainly consist of:

• Removing doors from metro stations;
• Increasing ventilation in tunnels between stations;
• Replacing existing air conditioning systems, where possible, with adiabatic cooling (with two systems that do not exchange heat with each other).