Airparif gives high marks to the car-free day – Le Parisien

BH | 28 Sept. 2015, 7:00 p.m. | Update: 28 Sept. 2015, 7:00 p.m.

We suspected a bit. But the result still deserves to be highlighted. According to surveys conducted by Airparif Sunday in different parts of the capital, the day without cars resulted in a decrease in the level of pollution … related to cars.

The body responsible for monitoring the air quality measured a “significant” less pollution by nitrogen dioxide (NO 2) in the areas closed to traffic with respect to a “classical” Sunday.

Up to 40% of emissions on the Quai des Célestins (IV); 30% on the Champs Elysees (completely pedestrian) and even 20% on the Opera Square yet located outer boundary of the perimeter without a car.

Small flat this balance of good taste Clean Air: Airparif engineers point out that traffic restrictions have had only impact “very local”, limited to areas without cars and their immediate surroundings. The car-free day is for example had no effect on pollution of the device, which rates No. 2 (slightly higher than) those of the reference Sunday have even been measured in early afternoon.

But some negative effects overs …

The bans put in place by the city of Paris concerned the very center of the capital, both wood and several periphery of micro-districts. In the rest of Paris (with the exception of the device) motorists were supposed to travel at 20 km / h maximum.

Airparif which has involved all its monitoring stations (as well as a mobile laboratory on scooter) not focused on measuring the levels of nitrogen dioxide. “This gas directly related to traffic and less sensitive to transfers as ozone or fine particles was the most appropriate tracer to measure the real impact of the car-free day,” says Pierre-Emmanuel Burg, engineer Airparif .

If the assessment proves very satisfactory in areas without traffic, the scientists note, however, that the operation has resulted in some “carry” effects. As in the Place de la Bastille, open to vehicles where a very high rate of 150 micrograms of pollutant per m3 was increased by mid-morning! “The measurement was made just before the introduction of the restriction of movement. The traffic was congested “explain the specialists

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