Europe’s air quality improves despite persistent pollution episodes – Report – EnviroNews

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Most of the air quality indicators across Europe continue to improve as emissions of regulated air pollutants decline, providing a clear indication of the success of long-standing air quality management policies, technological improvements and cleaner, more efficient industrial and transport systems. However, some parts of Europe still experience local air pollution situations and large-scale air pollution episodes persist.

Driven by a combination of emissions and seasonal weather conditions such as summer heatwaves, or extreme cold and temperature inversions in winter, these events have been recorded as exceeding limits set for health and environmental protection.

These are the findings of the latest Assessment Report on European Air Quality 2025, published by the Copernicus Atmosphere Monitoring Service (CAMS). Drawing on CAMS European air quality reanalysis data that assimilate observations from monitoring stations across Europe into the CAMS modelling systems, it details air quality trends and information on selected major pollution events, for the main pollutants regulated by the Ambient Air Quality Directive – ozone, nitrogen dioxide (NO₂₎ and coarse and fine particulate matter (PM₁₀ and PM_2.5), all of which pose risks to human and environmental health.

It is a critical milestone in the air quality policy calendar, essential to help national authorities, policymakers and air quality experts better understand the origins of pollution episodes and develop effective mitigation strategies.

Laurence Rouil, CAMS Director, said: “Our report is designed to provide national authorities, policymakers and air quality experts with insightful information to better understand both long-term trends and the origins of pollution episodes enabling more effective evidence-based decision-making. Europe continues to make steady progress in improving air quality thanks to sustained efforts to reduce emissions from transport, industry, residential heating, and other key sectors. At the same time, our report highlights and explains situations when the combination of emissions and meteorological conditions can still trigger significant large-scale episodes with exceedances of the limit values set for health and environment protection.”

Emissions are decreasing, policy works

Overall, the outlook remains encouraging, with air quality across Europe continuing to improve. Emissions of major air pollutants have steadily decreased thanks to decades of environmental policies, advances in technology, and cleaner approaches to industry and transportation.

Since 2015, emissions of sulphur oxides (SO_x) and nitrogen oxides (NO_x) have fallen by approximately 3–5% per year across the European Union, with the most significant reductions achieved in industry and road transport. Industrial emissions of SO_x have fallen by 59%, while NO_x emissions from industry have declined by 39%. Road transport emissions have also fallen substantially, with reductions of 40% for NO_x and 34% for PM_2.5.

These reductions highlight the effectiveness of European emission reduction policies. Despite continued economic activity, emissions are increasingly becoming decoupled from industrial production and transport demand. This progress is further supported by emission reduction commitments under the EU National Emission Reduction Commitments (NEC) Directive, which establishes legally binding national limits for each EU Member State to reduce key emissions that harm human health and the environment.

Temperature extremes influence seasonal air quality 

Despite progress in cutting overall emissions, the report warns that environmental pressures are becoming an increasingly important factor in determining air quality outcomes across Europe.

According to the European State of the Climate 2025 report, 2025 was the third warmest year on record in Europe, while also characterised by pronounced regional differences. These conditions had important implications for air quality across Europe. High temperatures, intense sunlight and stagnant atmospheric conditions created favourable conditions for ozone formation during summer, while prolonged dry conditions contributed to severe wildfire activity in parts of southern Europe. Colder-than-average conditions also contributed to elevated particulate matter concentrations during winter, largely as a result of emissions from heating systems.

Significant air pollution episodes in 2025 

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The CAMS report includes an in-depth analysis of four major pollution episodes that occurred in 2025. 

In February 2025, colder-than-average conditions in parts of Europe contributed to elevated PM_2.5 concentrations and exceedances of air quality health thresholds. Residential heating emissions played a dominant role in the episode, particularly in eastern Europe, while emissions from transport, agriculture and industry also contributed to elevated pollution levels. Exposure to unsafe levels of PM_2.5 is linked with respiratory and other health challenges.

Elevated concentrations of ozone – which can irritate lungs, worsen asthma, and even impact vegetation and ecosystems, reducing crop yields – were recorded during heatwave periods in June and August. The most significant ozone episode occurred between August 8 and 17, affecting western, central and southern Europe. High temperatures, intense sunlight and stagnant atmospheric conditions created favourable conditions for ozone formation across large parts of the continent.

Record wildfires that burned between August 11 and 19 heavily impacted Portugal and Spain and led to widespread exceedances of daily PM_2.5 limit values across parts of the Iberian Peninsula. For the first time, CAMS was able to quantify the contribution of wildfire emissions to particulate matter concentrations using advanced source attribution tools, providing new insights into how wildfire smoke affects air quality and public exposure to pollution. The episode demonstrated how prolonged dry conditions and wildfire activity can contribute to significant air pollution events, even as anthropogenic emissions continue to decline.

Paul Hamer, NILU senior scientist and main author of the report, said: “The wildfires in August 2025 showed how closely these hazardous events are connected to air quality. In addition to elevating the levels of particulate matter at the surface level, the fire plumes also contributed to the increase in surface ozone levels in northern Portugal and Spain, because the release of significant amount of ozone precursors which react in sunlight as the smoke travels.

“Additionally, long-range transport of Saharan dust frequently affected Europe during 2025, causing elevated PM₁₀ concentrations and numerous exceedances of air quality thresholds across southern, western, and central Europe. Analysis of a major dust intrusion during March shows that natural mineral dust transported from North Africa contributed significantly to elevated PM₁₀ concentrations in affected regions, underlining the importance of understanding both natural and anthropogenic sources when assessing air quality.”