Population Equivalent, background data and results

Published: 10-02-2020| Version 4 | DOI: 10.17632/6v7jnrcdpp.4
Contributors:
Nadia Mirabella,
Karen Allacker

Description

INTRODUCTION This excel files contains information and guidelines for the accounting of Population Equivalent, including collected and processed data. Information and data are calculated and accounted for the city of Leuven (Belgium), reference year 2016. Extensive information and full details about the present study are provided in "Towards a sustainable transition of cities: the Population Equivalent as a novel approach to implement urban Life Cycle Assessment studies", submitted to Science of the Total Environment (February 2020). GOAL OF THE STUDY Cities are very complex and unique systems, very diverse in terms of functions, and contexts, that provide a large range of services. not only for its inhabitants but also for additional groups of people. For these reasons, comparisons between cities can be difficult to perform and sometimes meaningless. The goal of the present study is to provide an enhanced functional unit (FU) to support LCA and urban sustainability studies. The enhanched FU takes into account not only the urban population as sum of its residents, but accounts also for the relative use of the existing services provided by the city to a larger audiance of city-users. These city-users are acknowledged based on previous researches about the functional categorization of cities, which each function comes with specific groups of city-users. This FU is based on the concept of Population Equivalent, popular in other domains of environmental engineering. Since the concept is able to summarize and normalize different entities to one single metric, it could be useful for: i) supporting the multi-functionality inherent to cities; ii) overcoming current limitations provided by other FUs; iii) overcoming comparability issues between cities.

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MATERIALS AND METHODS A four step approach is persecuted. First, an identification of the main function(s) of the city is performed. Secondly, for each identified group of city-users, information about the amount of people, the affiliation, and the main activity performed in the city are collected. Afterwards, the accountings regarding the relative performance of city-users are performed combining three main variables: i) relevant flows of mass and energy used per urban sector/service by each city-user; ii) share of use per sector/service by each city-user, applying a time-spent factor; iii) specific rules for responsibility of each city-user in the identified relevant sector of use (the distribution of these responsabilities between city-users is defined according to a weighting score. Finally, specific results are analyzed, summarized and normalized per group of city-users to a single metric, as absolute (total contribution), and per capita. The final result is a coefficient, the Population Equivalent value, that can be multiplied to the number of residents in order to identify the additional amount of people using the services of the city.