WP1: Measurement framework, and primary methods for measuring the aerosol absorption coefficient of airborne particles

The ultimate goal of this work package is to establish SI traceability for primary methods to measure the light absorption coefficient of airborne particles. The provision of a framework for the underlying physical measurement will underpin the other technical work packages, WP 2 being the provision of a calibration source with known properties and WP 3 being the transfer of primary capabilities to field instruments, including those based on filter sampling.

WP2: Black carbon aerosol generator development and characterisation

The solution to the problem of providing traceable calibration to common field black carbon instruments, such as those collecting aerosol particles on filters, will involve using an appropriate source of generated material. This will either be used directly, by providing a known concentration of black carbon, or indirectly, as a variable source of black carbon, not reliant on ambient concentrations, that can be introduced to both the field instrument and a reference instrument in parallel. Ideally a source generating “pure” black carbon would be available. Although black carbon sources exist, for example based on diffusion flame generators, they typically also generate a significant amount of organic carbon, and there is a clear need to identify or develop the best sources for calibration purposes, and to characterise their output using the primary traceable methods of WP1.

The aim of this work package is to investigate several candidate reference methods for use as near-black carbon sources to generate a reproducible and stable calibration aerosol with known, suitable properties. The candidate methods include diffusion flame generators, graphite spark generators, fullerene black carbon, colloidal graphite (Aquadag) and black polystyrene latex spheres. Because it is anticipated that some sources will be less stable and reproducible in terms of concentration than of the particle properties, the work package also includes methods for monitoring the output of the source independent of the aerosol absorption.

WP3: Traceable calibration for field black carbon monitors

The high significance of BC with respect to both climate change and health effects has been globally recognised, and very large numbers of field measurements are carried out, as part of international or national monitoring networks, or as part of studies investigating local sources or personal exposure. Reliable and traceable ambient measurements are necessary for these measurements to be comparable across the world and consistent over long time periods. Field instruments typically measure the light absorption of particulate matter after it has been collected on a filter, rather than in its airborne state, introducing large correction factors and needing calibration.

The SI traceability for light absorption, established in the WP1, will be brought to filter-based field instruments through laboratory evaluation and field trials in WP3. WP3 will take into account the main findings and outputs of WP1 (i.e. primary particle absorption measurements) and WP2 (i.e. black carbon aerosol generators), to propose a traceable calibration procedure aimed at ensuring increased consistency between instruments’ outputs as well as to improve the accuracy and reliability of the data.

WP4: Creating impact

The aim of this work package is to maximise the value and impact of the scientific work delivered by the project through a combination of interaction with the main stakeholders and end-users, including two-way information exchange, input into European standards, assisting Member States to comply defensibly with existing legislation, evidence based outcome to help formulate improve policy and metrics, practical help and training for end users, and facilitating commercial exploitation of the results by European-based businesses.

The whole intention of the project is to have a significant and measurable impact on air quality and climate-focussed studies, and on the confidence and comparability with which air quality legislation is delivered across Europe, within the project lifetime. The impact work package is geared towards ensuring these important outputs are delivered properly and promptly.

WP5: Management and coordination

The aim of this work package is to provide a description of the management and coordination in order to ensure a successfully run project. Details of the plans for reporting and meetings are also specified. A project management board (the coordinator and WP leaders) will be created to monitor project activities, to facilitate the completion of deliverables by set deadlines and to take responsibility for frequent communication between the partners.