Figure 1: Material intensities of residential buildings
Units: tons / m2 of total Gross Floor Area of Housing Units
Spatial Unit: Census Tracts 2021
Note: Census tracts with residents less than 4 individuals or dominated by other land use rather than residential/urban were discarded.
As part of the process of developing a joint model to analyze energy flows and material stocks in urban areas, the CircEUlar partner INEGI has currently concluded the estimation of material stocks in both buildings and mobility infrastructure for one of its case studies, the city of Porto. This spatially-explicit estimation integrating detailed local data collected from the local municipality, combined with open source information (such as OpenStreetMaps) and material intensity factors (as estimated by Wiedenhofer et al. (2024)), has revealed interesting spatial patterns, as shown in Figures 1 and 2.
The material intensities of residential buildings highlights the city centre as the area with the highest material intensities (presumably due to clustered building patterns alongside the use of heavy materials – e.g. stone), followed by areas of high-rise buildings (recent constructions, mainly made of concrete). Low- and medium-density neighborhoods suggest more balanced materials intensities. The material intensities of mobility infrastructure highlights that more peripheral areas within the city, also linked with more recent development patterns, seem to be more material intensive, anchored in heavier infrastructure, in particular highways and expressways.
Globally, the jointly analysis of the geographical patterns of materials intensities suggests that certain development patterns are more material-intensive, and represents an important insight for urban planning as they can inform circularity strategies to avoid the material lock-in of urban areas, with an important focus on design.
A preliminary modeling of the estimated material intensities for both buildings and mobility has produced encouraging results, with very significant explanatory power attributed to the built environment variables. Such type of analysis is expected to provide valuable support to local authorities and urban planners towards sustainable and circular development strategies for physical urban elements, and informing pathways to narrow, slow, and close the use of materials in cities, in a spatially-explicit way.
Figure 2: Material intensities of infrastructure (car roads, rail, and metro networks)
Units: tons / m2 of total Gross Floor Area of Housing Units
Spatial Unit: Census Tracts 2021
Note: Census tracts with residents less than 4 individuals or dominated by other land use rather than residential/urban were discarded.
By Paulo Batista – INEGI