This is a report resulting from the research project TESS - Traffic Emissions, Socioeconomic valuation and Socioeconomic measures that is financed by EMFO. In 2002 an agreement about the EMFO programme was reached between the partners from the Swedish Vehicle Research Council, PFF. EMFO is a sector-wide research competence to develop vehicles and vehicle components with emission levels that are sustainable in the long term. The aim of EMFO is to offer academia, industry and authorities access to necessary knowledge and pioneering solutions that are necessary if vehicle technology is to develop in the desired direction. One important task is to coordinate activities within the programme with both national and international research in the field. EMFO comprises subsidiary programmes and two of these were: "Socio-economic evaluation of the health and environmental impact of different emissions" and "Optimal range of socio-economic measures". TESS undertakes research in these two areas but it is also related to the subsidiary programme: "Health and Environmental Impact". The application was approved in 2005 and the project runs during 2005-2008. The basis for the research in TESS is the valuation methods developed in the EU funded ExternE projects where the external cost of emissions is calculated by tracing the effects that the emissions have on human health and then valuing these effects. The aim is to calculate the external costs related to particles that local emissions (from traffic and other sources) generate on a local and regional scale using Stockholm as a case study. Based on this information an analysis will be made on what reductions measures are likely to be efficient from an economic point of view.