Are low-emission zones unfair?

Charlotte Liotta, November 2024

The Conversation

To download : directive_200850ce_parlement_europeen_qualite_air.pdf (420 KiB)

Three letters have caused a lot of ink to flow. These are LEZ, which stands for low emission zones, areas generally located in city centres where the most polluting vehicles are restricted in order to reduce air pollutant emissions and improve air quality. In France, they have been mandatory in cities with more than 150,000 inhabitants, subject to air pollution levels, since a law was passed in August 2021.

However, this measure remains highly controversial. On 26 March, the special parliamentary committee responsible for examining the bill to ‘simplify’ low-emission zones (LEZs) voted in favour of abolishing them.

Many critics see it as an unequal measure that would mainly penalise the poorest households, which often own more polluting vehicles. What is the situation in practice? To answer this question, we have sought to explore the impact of LEZs in terms of inequality in eight French cities.

Proven health benefits

Let’s start by looking at whether the intended effects of LEZs are being achieved in practice. Although relatively few in number, existing studies show that LEZs do, in most cases, have a significant impact on air quality and residents’ health, and help reduce greenhouse gas emissions.

In Europe, most LEZs have reduced air pollutant concentrations, with effects ranging up to a 32% reduction in nitrogen dioxide concentrations in Madrid. The health benefits are also clear: by lowering concentrations of fine particulate matter PM10 (with a diameter of less than 10 micrometres) and PM2.5 (with a diameter of less than 2.5 micrometres), LEZs have helped reduce the incidence of respiratory and cardiovascular diseases and lower premature mortality linked to pollution in Germany, according to two studies.

However, these benefits primarily accrue to the residents of LEZs themselves: in Paris, for example, the LEZ mainly benefits the wealthiest populations living in central Paris, who were the most affected by poor air quality before the LEZ was introduced. However, this result is largely contextual: in Brussels, on the contrary, it is the poorest residents who benefit most from the LEZ, as they are more likely to live in the city centre, within the LEZ perimeter.

Nevertheless, the issue of the equitable distribution of these health benefits remains largely absent from the public debate, which often focuses on equity in access to mobility.

A highly controversial measure

The impacts of LEZs in terms of mobility are much more controversial. Among the arguments frequently put forward are that LEZs undermine residents’ right to mobility and are being introduced too quickly to allow residents to adapt, leading to protests by motorists’ and residents’ associations. They are therefore often described as ‘social bombs’ that generate exclusion, as the poorest residents are inevitably the most affected since they often own more polluting vehicles.

To understand the scale of these controversies, one need only look at the timetable for the introduction of LEZs, which has been modified and delayed numerous times. In Grenoble, for example, the ban on Crit’Air 2 vehicles has been postponed from July 2025 to 2028 in order to improve alternative transport options for residents. The Aix-Marseille metropolitan area has also abandoned its ban on Crit’Air 3 vehicles, initially planned for September 2023, while the Lyon metropolitan area has postponed the ban on Crit’Air 2 vehicles until 2028.

Are these fears justified? Surprisingly, there have been few scientific studies on the impact of LEZs in terms of social justice. Our study therefore aimed to remedy this by analysing the expected impact of LEZs on residents’ access to employment in eight French cities where LEZs are currently being introduced: Grenoble, Marseille, Montpellier, Nice, Reims, Rouen, Strasbourg and Toulouse. These cities have published a timetable for the gradual ban of polluting vehicles, from Crit’Air 5 (the most polluting) to Crit’Air 1 (the least polluting). In our study, as all cities are at different stages of LEZ implementation, we consider the impact of LEZs affecting vehicles classified as Crit’Air 3 to Crit’Air 5 or unclassified.

Access to jobs, i.e. the number of jobs an individual can apply for based on their socio-professional category and travel time, plays a decisive social role. Unsurprisingly, research shows that poor access to employment reduces the chances of finding a job and increases the risk of long-term unemployment. We therefore compare access to jobs before and after the implementation of LEZs for six socio-professional categories (farmers, craftsmen/traders, managers/senior professionals, intermediate professions, employees, manual workers) in our eight cities.

Our results show that the criticisms levelled at LEZs appear to be justified: losses in access to employment, which can be interpreted as the percentage of jobs that are no longer accessible following the introduction of LEZs, are significant in cities that have implemented ambitious LEZs. They can reach more than 20% on average for certain socio-professional categories in Grenoble, Montpellier, Rouen, and Strasbourg. In fact, after the introduction of the LEZ, some commutes become longer because the home or workplace is located in the LEZ, because the household owns a polluting vehicle, and because the alternative by public transport or on foot is longer. In terms of inequality, the most affected are employees and manual workers (CSP5 and CSP6) in six of the eight cities: Grenoble, Montpellier, Rouen, Strasbourg, Nice, and Toulouse.

Where do these inequalities come from and how can they be addressed?

We then asked ourselves where these inequalities came from, as a better understanding of their factors allows us to devise appropriate strategies to address them.

Our results show that, although it is mainly the wealthiest people who live and work in the LEZ and are therefore more directly affected, the poorest people own more polluting vehicles and are less likely to be able to travel by public transport or on foot, as they live or work further away from public transport and their homes and jobs are too far apart to make walking possible.

However, these results vary from one city to another. For example, the two cities in which LEZs do not affect employees and workers more (SOC 5 and SOC 6) are Reims and Marseille: in Marseille, because public transport is relatively accessible to employees and workers, and in Reims, because the poorest households own few polluting vehicles and few live in the LEZ. But even in these cases where the impacts of LEZs are evenly distributed across socio-professional categories, it remains more difficult for the lowest-income households to adapt by purchasing new, less polluting vehicles, as the cost of these vehicles weighs more heavily on their budget.

These results highlight the potential pitfalls of current public policies. Numerous subsidies exist to encourage the purchase of less polluting vehicles; however, as the lowest-income households are more likely to own polluting vehicles but less likely to live in LEZs, it is not certain that they are the ones who benefit most from these subsidies. Subsidies that specifically target the lowest-income households, such as the conversion bonus or the eco-bonus, should therefore be prioritised.

In addition, cities grant exemptions from LEZs, allowing access to LEZs for low-mileage drivers or certain commercial vehicles, for example. However, these exemptions could be modified to take into account residents’ income, for example by granting low-income residents additional time to change their vehicles.

In the longer term, it remains crucial to guarantee access to public transport for all: Montpellier, for example, has made public transport free for its residents in parallel with the introduction of its LEZ. However, such measures are ineffective if they are not accompanied by an expansion of services, enabling public transport to benefit everyone, which can be difficult to implement in practice. Improving urban quality of life and reducing emissions without increasing mobility inequalities requires a coherent set of public policies focused on reducing inequalities and combining short- and long-term strategies.

Sources

To go further