Multiscale Approach to Life Cycle Assessment

The urban environment is characterized by multiple interactions between its parts, and any change can determine a modification in its metabolism. Typically life cycle assessment (LCA) takes into account only part of the interactions. The main aim of this study was to present a hybrid analysis for enhancing the spatial resolution of LCA, focusing on surface albedo evaluation. In this article the substitution in New York City, New York, USA, of traditional roofs with a mean albedo of 0.32 with white roofs with an albedo of 0.9 has been hypothesized. A multiscale approach was used to evaluate the impact of variation in urban albedo, since it can influence the urban heat island (UHI), energy use, and atmospheric chemistry, affecting radiative forcings. The impact on global climate has been translated, through the use of a climatological model, into equivalents of carbon dioxide and added to the impact of the white roof. The effect of the summer UHI mitigation on human health has been assessed through the use of a hybrid model. Finally, the environmental burdens of a square meter of roof have been evaluated by considering the elementary flows—excluding the energy use—and added to the results deriving from the evaluation of the effects on human health and on climate change. In time horizons of 50 and 100 years, it shows that the increase in rooftop albedo plays an important role in decreasing the impact of rooftops on the climate‐change and human health impact categories.