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The new European Union directive on ambient air quality entered into force at the end of 2024. However, the new limit values ​​will start to apply from 2030. In order to prepare for these changes, member states will assess air quality simultaneously according to the current and new rules from 2027. Therefore, the Slovak Hydrometeorological Institute (SHMI) compared the monitoring results with the requirements of the new directive for the first time in the assessment of 2025 as part of the Air Quality Report. The results show where further measures will need to be taken in the coming years.

It's not just lower limits

The new directive does not only bring lower permitted concentrations of pollutants. In some cases, it also changes the evaluation method itself.

For dust particles PM₁₀, for example, the daily limit value is reduced from 50 to 45 µg/m³, and at the same time, the number of days during which it can be exceeded is reduced from 35 to 18 per year. Even short-term episodes of deteriorated air quality will thus have a greater impact on the overall assessment.

Dust particles remain the biggest challenge

Although the year 2025 was among the more favorable years from the point of view of PM₁₀ concentrations, and some of the lowest values for the last period were measured at several monitoring stations, the situation is less favorable when compared to the limits that will apply from 2030.

According to the results for 2025, 12 monitoring stations in seven zones of Slovakia would exceed the new annual limit value for PM₁₀. With a daily limit, there would be 11. This is not a deterioration of air quality, but a consequence of stricter assessment rules. Even more demanding requirements await dust particles PM_2.5. According to data from 2025, the new annual limit of 10 µg/m³ would be exceeded by the majority of monitoring stations, and the daily limit would not be met at up to 33 of them. At the same time, the results show that the further reduction of concentrations during the heating season will be crucial, as local heating contributes significantly to air pollution.

The problem also remains with transport

According to the currently valid limits, the annual limit value of nitrogen dioxide was not exceeded at any monitoring station in 2025.

However, after comparison with the limits that will be applied from 2030, the new annual limit value would be exceeded by five monitoring stations - in Bratislava, Košice, Prešov, Banská Bystrica and Trenčín. Meanwhile, regional background stations already meet the new requirements with a sufficient margin.

Ozone will be under stricter supervision

The new directive also tightens the assessment of ground-level ozone. The allowed number of days exceeding the target value is reduced from 25 to 18.

If the limits valid from 2030 were already applied today, five monitoring stations, especially in the south-west of Slovakia, would not comply with them. These are areas where the formation of ozone is supported by high summer temperatures, intense sunlight and the presence of emissions from transport or other sources.

Not all pollutants will be a problem after 2030

Carbon monoxide concentrations remain below the new limit values, and Slovakia meets them with a significant margin. The situation with sulfur dioxide is equally favorable, where the new annual, daily or hourly limit was not exceeded either. Even benzene is not currently a problematic pollutant, and even after the tightening of the limit value, there remains a sufficient reserve to fulfill it in most of Slovakia.

What does this mean?

The monitoring results for 2025 show that air quality in Slovakia has been improving over the long term. However, they also indicate that meeting the limit values ​​that will come into effect from 2030 will be a challenge in several locations.

The greatest attention will have to be focused on reducing emissions from local heating and road transport. These will be crucial for Slovakia to be able to meet the stricter requirements of the new European legislation.

The new directive also brings monitoring of new pollutants

The tightening of limit values ​​is not the only change. The new directive also expands the scope of air quality monitoring to include so-called pollutants of new interest, for which knowledge about their impact on health is gradually deepening. At selected monitoring sites (so-called supersites), the following will be monitored in particular:

• ultrafine particles (UFP), which are so small that they can penetrate deep into the lungs and potentially into the bloodstream, 

• black carbon, which is mainly produced by incomplete fuel combustion and is a significant indicator of emissions from transport and local heating, 

• ammonia (NH₃), mainly from agricultural activity, which is involved in the formation of secondary dust particles.

Another novelty is the establishment of the above-mentioned supersites - specialized monitoring stations, which will monitor a wider spectrum of pollutants and their mutual connections. The aim is to obtain a more detailed picture of the composition of the air, better identify sources of pollution and prepare more effective measures to reduce it. SHMI is planning 2 sites; one in an urban environment and one in a regional environment; with an expanded range of measurements and more detailed data, namely on Mamateyova Street in Bratislava and in Stará Lesná.

Quality data only makes sense if it reaches the people

The new directive emphasizes that health protection does not only start at the measuring stations, but also with informing the public. Member States should ensure that air quality data is easily accessible, understandable and regularly updated. The public should have access not only to current concentrations of pollutants, but also to information about their possible health effects and recommendations on how to limit exposure during episodes of poor air quality. Particular attention is paid to sensitive population groups, such as children, pregnant women, seniors or people with respiratory and circulatory diseases.

The new directive does not only mean stricter limits and more modern monitoring. Its goal is to make air quality data a practical tool for health protection not only for experts and policymakers, but also for anyone who wants to know what kind of air they breathe.

You can follow the current state of air quality and other practical information at www.dnesdycham.sk and www.shmu.sk.