In the IMBALANCE project the physical and chemical properties of emissions caused by the intended burning of biomass for cooking and heating will be comprehensively characterized in order to allow an assessment of their impact on air quality and climate. Economic modeling will be used to assess the external costs of biomass burning emissions in comparison with alternatives. In the first 2 years of the project, the emphasis will be placed on wood combustion produced aerosols, with emissions from non-wood biomass combustion to be assessed in years 3-4.