Implications of climate change and changing biomass burning patterns for Austrian air quality

In Austria, use of biomass for the provision of space heat is widespread and biomass from wood plays an important role in phasing out the use of fossil fuels to decarbonise the energy use in the building sector. However, biomass combustion is attributed with higher emissions of particles and particle-bound pollutants compared to combustion of oil and gas. There is a conflict of objectives between switch to renewables by use of biomass and lowering the concentration of particles in ambient air in order to protect human health. This conflict of interest will become even more challenging with the implementation of the upcoming revision of the Ambient Air Quality Directives. The revised Ambient Air Quality Directive foresees considerably lower limit values for particulate matter (PM10 and PM2.5) to approach the air quality guideline levels by the World Health Organization, WHO. The proposed limit values are currently being exceeded in many regions, the WHO air quality guideline levels for PM10 and PM2.5 in almost all regions of Austria. A data-based resolution of this conflict of objectives at regional level has not been carried out so far – mainly due to uncertainties regarding spatially distribution of heating technologies, fuels used and emission factors. Furthermore, no emission scenarios are available on local/regional levels. These data gaps pose the risk that measures will be taken unilaterally in favour of one target and that the resulting lock-in effects will cause high costs. The results of this project will support decision makers on national, regional and local level and users in the interdisciplinary balancing of the objectives. The project identifies in a first step regions in Austria with (a) concentrations at risk for exceeding the future PM10 and PM2.5 air quality limit values and WHO guideline levels, and (b) a – current and potentially future – high share of biomass burning for space heating. As a next step, the project will improve – for the identified regions at risk – the completeness and quality of data about type and amount of fuel used, types and technologies of heating appliances and emissions. This is done in close cooperation with experts of administrations at federal province and local level.