European air is cleaner than it was twenty years ago. This is a fact, documented by the European Environment Agency in its annual report published in April 2026: emissions of fine particles and nitrogen oxides have declined significantly since the early 2000s, and premature deaths attributable to PM2.5 have been cut in half over two decades. This progress did not fall from the sky — it is the result of vehicle regulations, industrial standards, and, in several cities, low-emission zones maintained with consistency despite their unpopularity.

And yet. In 2023, 63,000 people died prematurely in the European Union because of ozone. Not fine particles, not nitrogen dioxide: ozone, that secondary pollutant that forms when NOx and VOC emissions cook in summer heat. It is a signal that something has changed about the problem. The decline in direct emissions is real. But the climate is transforming a residual pollutant into a growing threat, and the policies that made it possible to contain the curve are beginning, in several countries, to retreat. France provides the clearest example.

The Essentials

  • 63,000 premature deaths linked to ozone in the EU in 2023, according to the April 2026 EEA report — a cause of death greater than most road accidents
  • Premature deaths linked to PM2.5 have been halved in Europe since 2000, thanks to industrial standards and low-emission zones
  • Still 20% of European monitoring stations exceed EU standards for PM10 and ozone; geographic inequalities remain pronounced
  • In spring 2026, an attempt to eliminate LEZs (Low-Emission Zones) was struck down by the Constitutional Council, but the political signals sent call into question health gains that took decades to accumulate
  • EEA projections to 2040 suggest that without maintenance of emission reduction policies, intensifying heat waves will erase part of the progress made since 2000

Twenty Years of Progress That Public Debate Ignores

The balance sheet is stubborn. Between 2005 and 2023, European PM2.5 emissions fell by 38%, NOx emissions by more than 40%. Nitrogen dioxide concentrations in cities have retreated measurably, particularly where low-emission zones have been maintained. EEA epidemiological models estimate that these changes have prevented hundreds of thousands of premature deaths over the period.

This is not a natural phenomenon. It is the result of specific political choices: successive Euro standards on vehicle emissions, European directives on national emission ceilings, public investments in public transport, and, in major urban areas, the gradual introduction of traffic restrictions. Germany, the Netherlands, and Belgium built these devices over ten to fifteen years. The data validate them.

Brussels and Antwerp are the most thoroughly documented examples. The Brussels low-emission zone, which came into effect in 2018 and was gradually tightened, contributed to a reduction in NO2 concentrations of approximately 37% between 2016 and 2022, according to a study published by HEAL and the Mutualités Libres. Antwerp has recorded comparable trends. These results are not spectacular in a media sense — they read in concentration curves, not in victory announcements. This is precisely why public debate ignores them.

Ozone Changes the Nature of the Problem

The fact that 63,000 people died prematurely in 2023 from ozone says something that statistics on fine particles alone did not capture. Tropospheric ozone is not directly emitted by engines or chimneys: it forms chemically in the atmosphere when precursors like NOx and volatile organic compounds react under the effect of solar radiation and heat. The reduction of NOx emissions therefore has a double effect: it decreases direct concentrations, and it should, in theory, reduce ozone formation. In practice, the relationship is not linear, and rising temperatures come to offset the gains from emission policies.

That is where the problem tips. Europe has made real progress on emissions. But it faces summers that last longer and heat more intensely. Each heat wave episode is a chemical reactor in the open air that transforms residual emissions — even when reduced — into ozone at dangerous concentrations. The 63,000 deaths in 2023 are not a sign that air quality policies have failed: they are a sign that their horizon must be pushed back, and their ambition maintained, in the face of a new physical constraint.

The EEA states it clearly: without continued emission reduction policies toward 2040, the foreseeable intensification of heat waves risks erasing a significant portion of the health gains accumulated since 2000. This is not a catastrophist projection — it is an accounting exercise. Emissions cut in half and a doubling in the frequency of heat waves can result in ozone concentrations identical to those of the 2010s. The movement of progress does not disappear: it simply requires being extended to remain visible.

20% of Stations Still Exceed Standards: A Geography of Inequalities

The April 2026 EEA report does not paint a uniform picture. While long-term trends are positive, 20% of European monitoring stations still record exceedances of EU standards for PM10 and ozone. This figure hides a specific geography that national averages erase.

The most exposed areas remain dense city centers, industrial corridors, and regions where topography traps pollutants — Alpine and pre-Alpine valleys, certain Mediterranean basins. These are also, most often, areas where the proportion of low-income residents is higher: they cannot afford to leave in the summer, they live in the most poorly insulated apartments, they are least likely to have a recent car or a job compatible with telework. Air quality is a public health issue. It is also a justice issue.

Central and Eastern European countries generally show higher PM2.5 concentrations, partly due to greater dependence on coal for residential heating — a source that automobile-focused LEZ policies do not address. Progress is therefore unequal in its geography as in its causes. It calls for differentiated policies, not a one-size-fits-all response.

France Chooses Retreat

It is in this context that the spring 2026 events take on their full significance. Faced with protests from motorists and pressure from several local officials, an attempt to completely eliminate Low-Emission Zones was incorporated into a simplification law. But the Constitutional Council struck down this measure on May 21, 2026: LEZs remain legally in effect. Practical relaxations exist nonetheless in certain metropolitan areas — absence of fines in Île-de-France, expanded exemptions — without there being any formal legislative easing of access criteria.

The political reasoning is intelligible: LEZs are perceived as unjust by households that cannot afford to change their vehicle, in territories where the alternative to the car remains insufficient. This tension is real. It is not an invention of device opponents. A household on the urban periphery working irregular hours and unable to afford a car compliant with new standards bears the cost of a policy that imposes expenses it cannot absorb.

But regulatory retreat is not the answer to this tension. It defers the cost in time, it does not eliminate it. It transfers it from mobility to health, from the active individual to the healthcare system and health insurance funds, from working adults to children and the elderly. Epidemiological studies on the health effects of LEZs — notably those conducted in Madrid and London, two cities where the device has been maintained consistently — show measurable decreases in hospitalizations for respiratory and cardiovascular conditions in affected perimeters. These benefits take years to materialize. They also fade away in just a few years when policies retreat.

France is not alone in this dynamic. Several European cities have experienced challenges to their devices under populist or judicial pressure. But French turbulence is notable for its timing: it occurs precisely when EEA data confirms that the ozone problem is itself worsening, and that maintaining pressure on NOx emissions is the only variable that public policies can still control in the climate equation.

What Brussels and London Understood That Paris Is Retreating From

The comparison with Brussels is instructive, not because the city would be a perfect model, but because it illustrates what constancy produces. The Brussels low-emission zone was initially contested. Oppositions were strong, exemption requests numerous. The city held firm on access criteria, but invested in parallel in alternatives: expansion of the public transport network, conversion grants for low-income households, development of cycling as infrastructure rather than as a marginal option.

The result does not read in a victory announcement: it reads in NO2 curves, in studies by Bruxelles Environnement and HEAL, in hospital statistics. It is this combination — maintaining regulatory constraint and investment in alternatives — that produces results, not one or the other alone.

London, with its Ultra Low Emission Zone progressively extended since 2019, provides the same lesson. Available evaluations report a marked reduction in NO2 concentrations in zones covered by the ULEZ compared to pre-ULEZ levels, and a decline in hospitalizations for childhood asthma in affected boroughs. The device was also contested — vigorously, upon its extension to outer zones in 2023. Sadiq Khan maintained the policy. The data vindicate him.

What these experiences show is not that constraint is popular. It is not. What they show is that support for the accompanying policy — funding alternatives, support for modest households during the transition — is the determining factor in acceptability over the medium term. Where cities invested in both legs of the device, contestation attenuated. Where regulation advanced without alternatives, rejection flourished.

France pursued both halfway: LEZs without sufficient funding for alternatives in affected metropolitan areas, conversion grants insufficient for modest households, public transport that did not progress quickly enough to offer a credible alternative. The solution to this problem was not to erase the regulation. It was to accelerate investment in alternatives. The two did not advance at the same rate, and it was the weaker lever that ultimately gave way.

The Health Debt of Inaction Is Repaid in Twenty Years

EEA projections to 2040 are not prophecies. They are models based on long data series in climatology and epidemiology, with named and debatable assumptions. But their central logic is sound: if summer temperatures continue to rise as climate projections suggest, and if emissions of ozone precursors cease to decline, ozone concentrations in European urban areas will rebound, despite progress made since 2000.

The burden of this rebound will not be distributed uniformly. Elderly people, children, and people suffering from preexisting respiratory and cardiovascular conditions are most vulnerable to ozone. They are also, massively, people who live in dense city centers and polluted peripheries, not secondary residences in rural areas. The reversal of the air quality curve is not an abstraction: it is a transfer of costs to healthcare systems, health insurance funds, and generations that will inherit a stock of chronic diseases that today’s policies could have prevented.

This mechanism is not different from the one governing other forms of implicit public debt. One can read in debates on economic models how economists as rigorous as Krugman and Aghion can evaluate differently the cost of immediate action versus the cost of delay. Applied to air quality, the debate is not theoretical: the cost of delay is documented, traceable, and, unlike many economic projections, hardly contestable.

The health gains accumulated since 2000 took twenty years to build. They can come undone in five to ten years if policies retreat and summers lengthen. France, in allowing pressure against its LEZ device to flourish in 2026, has not erased two decades of progress. It has slowed the accumulation of health capital at precisely the moment when climate demands that it be accelerated.

The Levers That Remain

It would be inaccurate to present spring 2026 France as a point of no return. The Constitutional Council’s striking down preserved the legal framework for LEZs. The European regulatory framework — the air quality directive revised in 2024, which aligns European standards with WHO recommendations — continues to weigh on member states. The European Commission has real means of pressure, and the jurisprudence of the Court of Justice of the EU on air quality standard exceedances has already forced several states to revise their policies.

The technical levers are known. Policies to reduce methane emissions, which contribute to ozone formation, have advanced in Europe in the agricultural and waste management sectors. Electrification of the vehicle fleet, driven by euro 7 standards and targets for phasing out combustion engines, structurally reduces NOx emissions from transport. These underlying trends do not disappear with regulatory retreat on LEZs.

What is at stake in the French decision, and in similar decisions by other European governments, is more the political credibility of regulatory continuity than the immediate destruction of health benefits. Industrialists, local authorities, and households making mobility choices over ten or fifteen years need stable signals. Every time a government retreats under pressure, it weakens confidence in the permanence of rules — and therefore, mechanically, it delays the investment and behavioral change decisions that would produce expected health gains.

The question for the coming years is not so much whether France will backtrack on its relaxations as whether it will finally be capable of building the social support that was missing from the initial device. Financing the conversion of the most modest households, massively investing in alternatives to individual cars in medium-sized metropolitan areas, calibrating transition aid on income rather than on vehicle type: these are policies costly in the short term and profitable over twenty years. It is precisely the type of calculation that democracies struggle to make — and that EEA data render, year after year, increasingly unavoidable.

Sources

  1. European Environment Agency, Air Quality Status Report 2026, April 2026 — https://www.eea.europa.eu/en/analysis/publications/air-quality-status-report-2026
  2. Bruxelles Environnement, annual reports on air quality in the Brussels-Capital Region
  3. Transport for London, ULEZ Evaluation Report, 2023
  4. World Health Organization, WHO Global Air Quality Guidelines, 2021
  5. Directive (EU) 2024/2881 of the European Parliament and of the Council on ambient air quality and cleaner air for Europe (2024 revision)
  6. EEA – Harm to human health from air pollution: burden of disease status, 2025 — https://www.eea.europa.eu/en/analysis/publications/harm-to-human-health-from-air-pollution-burden-of-disease-status-2025
  7. EEA – NEC Directive reporting status 2025 (emissions 2005-2023) — https://www.eea.europa.eu/en/analysis/publications/air-pollution-in-europe-2025-reporting-status-under-the-national-emission-reduction-commitments-directive
  8. European Commission – Road Deaths in EU 2023 — https://france.representation.ec.europa.eu/informations/rapport-des-deces-sur-les-routes-2023-le-nombre-de-morts-sur-les-routes-stagne-dans-lunion-2024-03-08_fr
  9. HEAL / Mutualités Libres – LEZ Brussels & Antwerp, 2023 — https://www.env-health.org/new-policy-brief-on-the-health-benefits-of-low-emission-zones-in-brussels-and-antwerp/
  10. London City Hall – ULEZ Facts, March 2025 — https://www.london.gov.uk/programmes-strategies/environment-and-climate-change/pollution-and-air-quality/ultra-low-emission-zone-ulez-london/ulez-facts
  11. Banque des Territoires / Localtis – LEZs and Constitutional Council, May 2026 — https://www.banquedesterritoires.fr/loi-de-simplification-les-zfe-remises-en-piste-apres-la-decision-du-conseil-constitutionnel
  12. Directive (EU) 2024/2881 – Ambient Air Quality — https://www.eea.europa.eu/en/analysis/publications/air-quality-status-report-2025