**1. Introduction**

The concept of environmental justice appeared in the last third of the 20th century, within the framework of "assessing the distribution of the benefits and damage caused by human agents between places and population groups, in order to determine whether or not serious discrimination exists" [1]. The general context was a growing awareness that the spatial distribution of some human activities was clearly discriminatory for one part of the population. For example, the generation, handling and storage of hazardous waste or the territorial distribution of certain pollutant industries tended to be located in areas occupied by the less favored part of the population. Environmental justice considers that "there is a universal right to nature" on all levels (individual, family, community, etc.), with the environment being understood as a common good [2]. Therefore, the basis of the concept is the non-discriminatory distribution of environmental benefits and damages and the need to establish participative decision mechanisms "that can distribute those benefits and damages equitably among a justice community made up of located entities (subjects and objects), both current and future, who may have unequal rights and obligations" [1].

From this perspective, environment justice or discrimination can be measured, in general terms, by calculating the overall computation (social, territorial and temporal) of the environment costs and benefits (which, in economic terms, are often called "externalities") generated by a certain activity or project, so as to later clarify whether the distribution of these elements among the various groups that may be affected by said activity in some way is fair. However, other authors uphold the inclusion of other, non-economic elements in

**Citation:** Alberich, J.; Pérez-Albert, Y.; Morales, J.I.M.; Picón, E.B. Environmental Justice and Urban Parks. A Case Study Applied to Tarragona (Spain). *Urban Sci.* **2021**, *5*, 62. https://doi.org/10.3390/ urbansci5030062

Academic Editors: Jesús Manuel González Pérez, María José Piñeira-Mantiñán and Juan Manuel Parreño Castellano

Received: 22 June 2021 Accepted: 13 August 2021 Published: 19 August 2021

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**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

the analysis, and choose to use indicators and variables of a different level of measurement, by applying multi-criteria analysis [3].

Different authors claim that, traditionally, the study of environmental justice has focused on analyzing the distribution of facilities with toxic emissions, waste dumps and other environment hazards that are disproportionately close to socially disadvantaged groups [4,5]. However, recent works have extended the scope of this concept to include terms such as equitable access to green areas and other natural resources [6,7]. This new interest is related to the conviction that urban parks or urban green areas help to increase the quality of life of city inhabitants because contact with urban nature as public parks promotes well-being and human health in cities [8] and urban residents can receive daily benefits [9].

An important issue shared by the literature we consulted is the actual definition of an urban park. Even though there is no single definition, the one provided by Jennings et al. [7] is considered appropriate (as it is necessarily broad), and states that urban parks are "a kind of green area that is generally public property and, consequently, accessible to the general public; and can include children's parks, leisure facilities and other characteristics that promote open air recreation". In order to analyze these urban green areas, they have been divided into categories according to their surface area and function in the urban space, according to their contents, different services, uses and the social values that they provide for different segments of the population [10,11].

There is consensus over the fact that, broadly speaking, ecosystem services imply benefits [12] in six different areas [13]: (1) they help to fight pollution [14] and contribute to microclimate normalization [15,16]; (2) reduce noise [17]; (3) improve the population's emotional wellbeing and psychophysiological balance by increasing the feeling of security [18]; (4) improve mental and physical health [19]; (5) promote outdoor life and social meetups [20] and (6) increase citizens' environmental awareness [9,21]. Therefore, ecosystem services regulate temperature and humidity, produce oxygen and filter radiation, absorb pollutants and muffle noise and, in addition, they provide an area for walking, relaxation and leisure. However, beyond their intrinsic value (their good organization, quality level or degree of protection), it is often their symbolic dimension which makes them places citizens appreciate.

Therefore, the World Health Organization considers urban green areas to be essential due to their inherent benefits for physical and emotional wellbeing [22]. A large portion of the works published on environmental justice regarding urban parks adopt a quantitative perspective. Qualitative approaches to this question are harder to find. In this respect, a notable exception is the work by Smiley, Sharma, Steinberg, Hodges-Copple, Jacobson and Matveeva (2016) [23], who analyze the opinions and preferences of minority ethnic groups regarding the use of the urban parks in Houston (Texas) using data obtained from two ad hoc surveys. From a quantitative orientation, GIS has been used to process the information. However, some authors have criticized the use of these tools, arguing that they specify the geographical units and threshold distances inappropriately and ignore the actual movement by people. Therefore, in some recent research, people have opted to use the georeferenced data produced by mobile telephones to obtain behavior patterns within green areas. These emphasize the real activities by park users, in terms of both space and time [24]. Another option is the application of a public participation GIS, such as the one used by Laatikainen, Tenkanen, Kyttä and Toivonen (2015) [25], which can provide an alternative to obtaining multifaceted knowledge on accessibility patterns. To establish the relationship between the distribution and quality of the parks and the population's socio-demographic characteristics, the Pearson correlation coefficient [26], the index of dissimilarity or an analysis of conglomerates is used [27]. Often, these parameters are accompanied by the use of statistical indicators to measure the significance of the observed differences, such as the Gini coefficient or the analysis of variance (ANOVA) test [10,28]. Equally, in comparative works between two or more cities, logistic regression techniques have been used to control and neutralize the different characteristics of the urban fabric

among the study cases [29]. Finally, another methodological aspect refers to the actual measurement of the social and environmental quality of the urban parks. In relation to this, some authors express the need to measure six parameters: access, services, security, social inclusion, visual and aesthetic quality and, finally, the ecological function [30].

From this perspective, in order to focus on efficient city management of community interests, we have to assess whether the population has access to green areas and, in addition, the quality of these areas in terms of, inter alia, the existence of vegetation and available or existing facilities or street furnishings. Therefore, the general objective of this work is to establish the degree of environmental justice in the urban parks in the city of Tarragona by establishing a Park Quality Index (PQI) and learning about the population's sociodemographic characteristics. To do this (1) a Multi-Criteria Evaluation (MCE) model was constructed within a GIS, which allows us to establish the PQI, (2) indirect, standardized indicators were determined for the socio-economic characteristics of the population living within 300 m or less of a park, such as the Synthetic Training Index (STI), the Human Development Index (HDI) or home sales prices in each sector, and (3) the PQI was correlated with the population's socio-economic characteristics to obtain the spatial justice results in terms of the availability and quality of urban green areas. The work is organized into six sections, plus the bibliography. The introduction reflects on the concept of environmental justice and reviews the methodological and conceptual aspects; the second section introduces the area of study; the third details the methodology stages and the tools used; the fourth reveals the results; the fifth contains the discussion and the final section includes the conclusions.
