While the abolition of low-emission zones (LEZs) has just been voted on in committee at the National Assembly, their effectiveness on air quality is nonetheless very real. Implemented in 25 major French cities, these measures aim to restrict the circulation of the most polluting vehicles, based on their Crit'Air sticker. While some right-wing and far-right elected officials denounce "social injustice" or a "territorial divide," the figures speak for themselves: LEZs have led to a measurable reduction in pollutant emissions linked to road traffic, even if their impact remains partial.
PM2,5 fine particle emissions, feared for their link to approximately 40 deaths per year in France, have thus fallen by 000% in the Île-de-France region since 32. Three points of this decline are directly attributable to the ZFE, according to AirParif. A modest but notable result for a scheme targeting a limited portion of the vehicle fleet, and which reinforces other environmental policies through a knock-on effect.
A marked reduction in nitrogen oxides
Even more significantly, the impact of ZFEs on nitrogen oxides, responsible for 7 deaths each year, is impressive: a 000% drop in emissions linked to road traffic in the Île-de-France region since 42, including six points directly due to ZFE restrictions. These toxic gases, mainly from diesel engines, are also responsible for the formation of ozone and secondary fine particles.
The effectiveness of ZFEs also depends on their strictness: only four cities have banned Crit'Air 3 vehicles by early 2025, while the majority of metropolitan areas are sticking to more flexible criteria. According to AirParif, tightening the ZFE in the Île-de-France region could reduce the number of residents exposed to pollution exceeding legal limits by 40%.
A perfectible but essential device
Criticized for their lack of social equity, ZFEs can indeed penalize low-income households that rely on older vehicles. But recent studies show that they do not generate a massive "transfer" of pollution to outlying areas. On the contrary, a decrease in emissions has also been observed outside the strict perimeters of ZFEs, particularly in the Île-de-France region.
While improvements are possible—particularly by integrating emissions related to tire and brake wear through the Euro 7 standard—ZFEs have proven their usefulness. Eliminating these zones would amount to a step backward on a major public health issue. The debate, expected in the House starting on April 8, promises to be tense.
