The implementation of a new pollution measurement system in the capital has made it possible to locate, with unprecedented precision, new sources of fine particle pollution in Paris.

A new technique for measuring fine particle pollution will be unveiled Tuesday in Paris. But the first tests already reveal an unprecedented map of pollution in the capital, with sources of particulate emissions that Parisians have hardly suspected so far.

You will not go over a metro mouth without thinking: very fine particles, that is to say less than 2 microns and a half, emerge, and there are 300 in the capital city. These invisible pollution clouds were detected by "Pollutrack": a system of sensors fixed on 400 electric cars that criss-cross Paris day and night.

"We knew the sources of pollution, but concerning the fine particles, we discovered hyper localized areas, very polluted that are not instinctively what we can have in mind," notes the microphone of Matthieu Belliard, on Europe 1 , Emmanuel Grégoire, the first deputy mayor of Paris. "We will have to install air treatment units before the extractors spit it out on the street, it will have to be done collectively, it will not happen the next day. RATP, but we will work with it, "says this elected.

The streets of the Marais and the "canyon effect"

Unlike Airparif's three fixed sensors, "Pollutrack" can spot very localized foci of particles, such as tour buses along the Champs-Elysées, poorly ventilated underground car parks or "canyon effect" streets. These are narrow streets where the buildings are very high, causing a particle traffic jam. The air coming from the device can get stuck on days of very weak wind, this is particularly the case of some streets of the Marais, in the center of the capital.

The 18th particularly affected by this pollution with fine particles. Motorized traffic not only involved but its reduction to the benefit of soft mobility is more than ever necessary and urgent. @ @ Mairie18paris mdb18e # / uRoHNCEz6H

- Paris in the saddle - 18th (@ pes_18e) September 16th, 2019

On the other hand, the Place de l'Etoile, which one would have thought polluted because of the dense traffic, is particularly well ventilated. These unprecedented measurements, which have not yet been validated scientifically, will be communicated to the public in the form of an online map, updated daily. It could also help to organize the city differently with green spaces or fountains placed in appropriate places to try to extinguish these different foci of pollution.