4sfera led the assessment of air quality monitoring networks across EU Member States to evaluate compliance with the new minimum requirements for sampling points under the revised Ambient Air Quality Directive, Directive (EU) 2024/2881.
The challenge
In 2024, the European Commission tasked 4sfera with evaluating whether the current air quality monitoring networks in all EU Member States complied with the new requirements introduced by Directive (EU) 2024/2881, which consolidates and revises previous directives (2008/50/EC and 2004/107/EC).
The key challenges addressed in this project were:
- Verification of compliance with the revised minimum number of sampling points per pollutant and type of area, as specified in Annex III of Directive (EU) 2024/2881.
- Evaluation of urban background coverage, ensuring at least one urban background station for PM2.5 and NO2 in each NUTS-1 region, and at least one sampling point per million inhabitants in urban areas exceeding 100,000 people.
- Assessment of monitoring for critical levels of SO2 and NOx, ensuring the required density of sampling points based on critical level thresholds and assessment thresholds set in Annexes II and III of the Directive.
- Harmonising data sources and methodologies across 27 Member States, considering variations in station classification (e.g. urban background, traffic, industrial, rural) and differences in monitoring strategies.
The solution
4sfera carried out a detailed assessment of the air quality monitoring networks in all EU Member States for the period 2019–2023. The evaluation followed the specific assumptions and technical criteria provided by the European Commission and reflected the updated requirements of Directive (EU) 2024/2881.
- Development of a comprehensive assessment framework to check compliance with the minimum number of sampling points for each pollutant and monitoring objective, following Annex III, points A, B, and C of the Directive.
- Integration of population and spatial data from Eurostat and EEA, to assess the per capita station coverage and the distribution of stations across NUTS-1 regions and large urban areas.
- Gap analysis to identify zones/agglomerations that lack sufficient urban background stations or hotspot stations, with a focus on PM2.5, NO2, benzene, CO, and other key pollutants.
- A detailed evaluation of critical level monitoring for SO2 and NOx, ensuring the presence of at least one station per 20,000 km² or 40,000 km², in line with the Directive’s spatial requirements.
4sfera produced individualised reports for each Member State, clearly identifying areas of compliance and highlighting gaps that require action to meet the revised obligations.
The result
- Delivery of 27 individual Member State reports, each providing a detailed assessment of national air quality monitoring networks against the requirements of Directive (EU) 2024/2881.
- Identification of specific zones and agglomerations within each Member State where the current number or type of sampling points does not meet the revised minimum requirements.
- A clear roadmap for Member States to strengthen and adapt their monitoring networks in anticipation of the full implementation of Directive (EU) 2024/2881, supporting the effective protection of human health and the environment.