As a first step a Background analysis was performed. That report assesses and summarises current Nordic knowledge, emission inventories and emission levels, and lays the basis for the emission measurement program which was performed in this second phase of the project. In order to improve the national emission inventories of SLCP, and reduce uncertainties, a better understanding of the emission factors for residential wood combustion is essential. Apart from emission factors, also national activity data on wood combustion technologies, fuel consumption and combustion conditions are important. This project contributes to a better knowledge base for emission factors for PM2.5, EC, OC, CH4, NMVOC and CO from residential wood combustion, as well as ratios for increased emissions at “bad combustion conditions” which can be weighted into the national emission factors, depending on national circumstances. Emission measurements were conducted on residential wood burning appliances, boilers and stoves, representative for the Nordic countries. There are substantial differences in the stock of residential wood burning technologies between the five Nordic countries, but the common technologies in all countries were covered. Measurements were made using EN standards for boilers and for stoves, and also the Norwegian standard for stoves. Sampling for PM2.5, EC and OC were in all cases done in a dilution tunnel (i.e. sample including condensables) and not in hot flue gases. The technologies tested were grouped according to similarities in technology and emission levels when developing the emission factors. In a national emission inventory, lack of very detailed activity data on technologies is the common situation, why the emission factor results were adapted accordingly. Generally the older technologies exhibited higher emission levels than more modern types of equipment. For example, the traditional log wood boilers had emission levels that were in the order of 5–10 times higher (depending on pollutant) than for the modern log wood boilers or pellet boilers. Among the stoves the difference was not as large, with up to 2 times higher emission levels from the traditional tiled and masonry stoves, and an older type iron stove, compared to the modern wood stoves.
The overall objective of this project is to improve the Nordic air emission inventories of Short Lived Climate Pollutants (SLCP). This project contributes to a better knowledge base for emission factors for PM2.5, EC, OC, CH4, NMVOC and CO from residential wood combustion, as well as ratios for increased emissions at “bad combustion conditions” which can be weighted into the national emission factors, depending on national circumstances. Den här rapporten finns endast på engelska.