16ENV07 AEROMET: Aerosol metrology for atmospheric science and air quality

• Forschungsstelle: METAS
• Projektnummer: F-5235.30087

Schlüsselwörter (Englisch)

Air Quality; Particulate Matter (PM); aerosol; fine particles, ultrafine particles; particle number; particle composition; particle number size distribution

Kurzbeschreibung (Englisch)

Measurements of aerosol particles are vital for enforcing EU air quality regulations to protect human health, and for research on climate change effects. Although metrics such as the mass concentration of airborne particulate matter (PM) including PM10 (inhalable particles with diameters of 10 micrometres and smaller) and PM2.5 (fine inhalable particles, with diameters of 2.5 micrometres and smaller) are currently in use the level of uncertainty is too high and the traceability is insufficient. Therefore this project aims to improve the uncertainty of particle mass, size and number concentration measurements and the characterisation of regulated components in airborne particles as needed by EU air quality monitoring networks.

Regulatory bodies, air quality networks and atmospheric instrument manufacturers all require the improvement of air quality monitoring, however there is currently a lack of traceable calibration standards and harmonised calibration procedures for measuring airborne PM. In addition, methods measuring PM10 and PM2.5 (particle mass concentration) within the EU Air Quality Directive 2008/50/EC need improving in order to ensure the comparability of local data measured by instruments relying on different working principles (e.g. gravimetric vs. optical measurements). Therefore, reference methods for measuring PM10 and PM2.5 and calibration methods for the instruments used for such measurement are needed.
The chemistry of aerosols (elemental composition analysis) is also part of existing regulation and necessary to understand their origins, behaviour, environmental fate and impacts (e.g. effects on health and climate). However, current methods for the quantification of regulated aerosol components (e.g. Elemental Carbon and Organic Carbon (EC/OC), metals, anions, and cations) are notoriously inflexible in terms of time and spatial resolution and are inaccurate. In addition, they do not meet requirements concerning detection sensitivity and flexibility for monitoring the temporal and spatial variability of air pollution. Therefore, validated methods for the determination of major components of PM are needed as well as reliable procedures for Mobility Particle Size Spectrometers (MPSS) and Condensation Particle Counters (CPC). Modern x-ray analytical techniques could also be used to improve the chemical analysis of airborne particles directly at their emission sources, therefore new SI-traceable X-ray techniques need to be developed.

This is a joint research project carried out in the framework of the European Metrology Programme for Innovation and Research (EMPIR) (see:http://www.euramet.org/research-innovation/empir/). The EMPIR initiative is co-funded by the European Unions's Horizon 2020 research and innovation programme and the participating states. METAS is one of the project partners in the Project.

Projektziele (Englisch)

The overall aim of the project is to develop and demonstrate methods for traceability and calibration of different aerosol instruments capable of covering the environmentally relevant size range from several nm up to 10 μm and the regulatory relevant mass concentrations (0.1 μg/m³ to 1000 μg/m³) and number concentrations (102 to 106 particles per cm³). The traceability and calibration will consider the above metrics as well as mass concentration and chemistry of particle components. The project also aims to provide the necessary EU wide calibration infrastructure for aerosol instruments. The specific objectives of the project are:

1. To develop reproducible reference methods for PM10 and PM2.5, including the design and building of a demonstration aerosol chamber system - for calibrating PM10 and PM2.5 instruments using representative generated aerosols and to achieve target uncertainties below 15 %.
2. To establish traceable validated methods for the determination of major components of particulate matter such as elemental and organic carbon (EC/OC), total carbon, anions and cations and major metals (e.g. arsenic, cadmium, mercury, nickel), in order to meet the data quality objectives of current regulation.
3. To develop calibration procedures for Mobility Particle Size Spectrometers (MPSS) for ambient measurements in the size range up to 1000 nm - in support of standardisation requirements from ISO TC 24 WG 12 and CEN TC 264 WG 32. In addition, to provide calibration facilities for measuring particle number concentration using Condensation Particle Counters (CPCs) in ambient air – as required by the standard FprCEN/TS 16976.
4. To apply mobile x-ray spectroscopy techniques combined within particle sampling techniques for quantifying particle compositions in the field for real time analysis. Results will be corroborated by a backup lab-based reanalysis of samples. To qualify a synchrotron based GIXRF setup as a traceable reference for a quantitative chemical aerosol analysis with mobile and bench top GIXRF instrumentation. Full traceability will be achieved by the use of fabricated micro and nanostructures and subsequently calibration along a complete traceability chain will be described in standard operating procedures (SOP).
5. To facilitate the take up of the technology and measurement infrastructure of the project by the measurement supply chain (accredited laboratories), by standards developing organisations (such as ISO TC 24 and CEN TC 264 and those linked to the EU Air Quality Directive 2008/50/EC) and end users (e.g. Network of National Air Quality Reference Laboratories (AQUILA) and the European Monitoring and Evaluation Programme (EMEP).