Assessing synergies and trade-offs between climate change mitigation and air quality effects of small-scale biomass heating in the residential sector

In the last decades, the EU has observed an increase in the use of biomass for energy, and for space heating in particular. Climate change mitigation strategies have favoured the use of wood-based biomass for heat and power supply, to reduce dependency on fossil fuels. However, it can pose risks for ambient air quality and public health, especially when used in small-scale building heating systems in cities. To leverage synergies and avoid trade-offs between climate change mitigation and ambient air quality, policymaking should be supported by quantitative analyses and robust evidence.

This paper presents a framework to assess potential life-cycle greenhouse gas (GHG) emissions and fine particulate matter (PM2.5) impacts on health of wood-based biomass use in small-scale residential heating systems. The framework draws on a life-cycle assessment (LCA) model, and it is applied to 87 EU cities in 23 countries (i) to quantify current GHG and PM_2.5 impacts associated wood-based biomass heating, and (ii) to two scenario analyses that evaluate potential trade-offs and co-benefits of climate change and air pollution mitigation actions. A complementary analysis is also performed to provide insight on the robustness of PM_2.5 results, comparing health effects associated with PM_2.5 using the LCA framework and city-specific emission and effect factors.

Results confirm strong correlation between GHG and PM2.5 impacts. Scenarios for GHG mitigation increased PM2.5 impacts of small-scale biomass heating per capita up to 14%, while those for PM2.5 mitigation reduced PM impacts up to 63%, with GHG mitigation co-benefits (reduction up to 50%) or trade-offs (increase up to 125%). The framework is widely applicable and provides robust results; and the scenario analyses demonstrate the importance of context-specific assessments to inform policymaking.