On October 14, 2024, the European Union took a major step forward in air quality regulation with the approval of a revised Ambient Air Quality Directive. This new directive signals a stronger commitment to public health by aligning more closely with the World Health Organization’s (WHO) latest air quality guidelines. With compliance targets set for 2030, the directive aims to significantly reduce exposure to harmful pollutants across Europe.
Following publication in the Official Journal of the EU, the directive entered into force 20 days later. Member states now have two years to incorporate the new requirements into national legislation.
A Landmark Move: Mandatory UFP Monitoring
One of the most impactful updates in the directive is the mandatory inclusion of ultrafine particle (UFP) monitoring. For the first time, all EU countries must include particle number (PN) concentrations and particle size distribution (PSD) measurements as part of their ambient air quality monitoring strategies. This marks a clear shift toward measuring not just how much particulate matter is in the air—but understanding its size, number, and behavior.
What’s New in the Directive?
1. Particle Number (PN) Measurements Required
In addition to mass-based metrics like PM10 and PM2.5, member states must now monitor ambient PN concentrations. These measurements provide a more sensitive indication of ultrafine particle levels, which are known to penetrate deeply into the lungs and contribute to a range of health problems.
2. Emphasis on Particle Size Distribution (PSD)
Monitoring PSD delivers crucial insights into how particles are distributed across different size ranges. This level of detail is essential for identifying harmful ultrafine particles and understanding how they move and interact within the atmosphere.
3. Compliance with European Measurement Standards
To ensure consistency across all member states, the directive mandates that PN and PSD monitoring be performed in accordance with:
- EN 16976 (published September 2024): Defines standardized methods for measuring ambient particle number concentrations, including sampling, conditioning, and data processing.
- CEN/TS 17434: Outlines technical specifications for measuring ambient PSD. This document is currently being updated for transition into a full European standard.
Technology to Meet New Demands
Meeting these new requirements calls for advanced, reliable instrumentation. TSI offers a portfolio of proven technologies already in use across Europe:
- Condensation Particle Counters (CPCs) like the Model 3750-CEN10 deliver accurate, real-time measurements of particle number concentrations down to 10 nanometers.
- Scanning Mobility Particle Sizer (SMPS™) systems pair CPCs with electrical mobility classifiers to measure particle size distribution with high resolution, delivering both PN and PSD data for comprehensive ambient air analysis.
These instruments are already widely adopted in EU research and regulatory initiatives—including ACTRIS and pilot UFP monitoring networks—and are now positioned to become integral components of national monitoring strategies.
Supporting EPAs in the Transition
The updated directive represents a pivotal moment for air quality and public health across Europe. It demands a shift from mass-only monitoring to a more nuanced understanding of particle number and size—offering policymakers the tools they need to act on the growing health risks posed by UFPs.
At TSI, we are ready to support Environmental Protection Agencies through every step of this transition. From selecting the right instrumentation to seamless integration into existing networks, our experts will help ensure compliance and elevate monitoring capabilities.
Get in touch to learn how we can support your UFP monitoring strategy.