The simplest direct impact of the research will be that measurements of black carbon become more accurate and more comparable than is currently the case in the aerosol monitoring networks across Europe, through the development of reference materials for black carbon, primary national facilities and traceable calibration mechanisms. In commercial terms it will give a direct advantage to European black carbon instrument manufacturers, who will have early access to traceable calibration facilities for their current instruments, and who will also make use of the facilities to develop innovative designs much more quickly than would otherwise be the case. It will also offer a great advantage to European manufacturers of aerosol black carbon generators of the type that will be developed within the project. End users will be government, environmental and citizen monitoring groups, who all employ black carbon measurement devices. Indirectly, the impact will be very widespread. In terms of scientific benefits, the improved measurements will be used directly within EU atmospheric aerosol projects, refining climate change models and mitigation proposals, and improving the quality of conclusions from cohort health studies looking at the effects of air pollution. Air quality measures to reduce black carbon emissions such as emission reduction and low emission zones have already been taken. However, traceable black carbon metrics to reliably quantify the success of these measures are not yet available, and will be addressed by this project. The project output is expected to provide the basis for new black carbon standards by European and International standards developing organisations like CEN and ISO. In terms of socio-economic benefits, the project output would potentially lead to revised air quality legislation, based on black carbon, for which reliable measurement methods would be available.