With a few exceptions, since January 4, 2021, Chartres (Eure-et-Loir) has been a 30km/h city.
Removal of lights, one-way street, cycle paths, the city of Carnutes has completely revised its traffic plan.
The objective “to calm the city” according to the municipality.
Three years after this driving revolution, what effects on air quality?
This is the question that the Chartràvélo association asked itself.
According to the cyclists' collective, reducing speed proves to be an effective lever for reducing fine particle emissions.
In 2023, annual averages have decreased significantly compared to 2019, proving the improvement in air quality.
“These figures show a downward trend in pollution levels, confirmed by a 40% reduction in the number of days where the PM10 threshold is greater than 45 µg/m3 between 2019 and 2023,” writes the president, Jérôme Bretonnière.
A spectacular drop in nitrogen dioxides
To support its study, the association studied the data collected by Lig'Air, an association responsible for monitoring air quality in Center-Val de Loire.
And the most remarkable drop is that of nitrogen dioxides (NO2) known for these harmful effects on respiratory health.
“The most significant impact of this measure is the spectacular 67% reduction in nitrogen dioxide (NO2) emissions in four years,” adds Adrien Soissons, communications manager.
So how can we explain this collapse in nitrogen dioxides?
These cyclists have an answer.
The speed limit favors other means of transport than the car.
“This encourages the massive modal shift of short-distance journeys made by car which are replaced by active modes or public transport” notes the association.
A truth which was already evident, a few months after the establishment of “city 30”.
ChartràVélo hopes, thanks to these results, for “a more generalized awareness in Eure-et-Loir” and is campaigning for the adoption by other cities of this measure which makes it possible to fight against atmospheric pollution.