Life Cycle Assessment of Land Use in Neighbourhoods

Urban sprawl and the increase of the built-up area have a major impact on land use. Buildings are responsible for two types of land use interventions: primary land use, i.e. the building footprint and secondary land use, associated with the resource extraction, production, transport and end-of-life treatment of construction products. However the environmental impact related to the primary land use is mostly not considered in current Life Cycle Assessment (LCA) studies of the built environment. The purpose of this paper is to assess the environmental impact of primary land use in neighbourhoods, considering not only the footprint of buildings but also the footprint of infrastructure and open spaces. Impacts related to land occupation and transformation are evaluated based on the impact assessment methods soil organic matter (SOM) (i.e. impact on soil quality) and Eco-indicator 99 (i.e. impact on biodiversity). An LCA study of neighbourhood models with diverse built densities, i.e. consisting of detached houses, semi-detached houses, terraced houses to compact apartment blocks, is performed. Moreover, buildings are simulated using combinations of building elements, from solid to timber frame structure. The results reveal the high contribution of primary land use to the neighbourhood life cycle environmental impacts, especially in low built density neighbourhoods. Furthermore, the environmental impact of primary land use is in most cases higher than secondary land use. Based on this analysis, it is recommended to include the assessment of primary land use in neighbourhood LCA, especially in studies comparing different built densities.