The absence of green areas in cities has negative impacts on the health of its inhabitants. The lack of access to these green areas in a thousand cities of 31 European countries – the 27 of the EU plus the United Kingdom, Switzerland, Norway, and Iceland – are behind almost 43. 000 annual deaths, according to estimates from a study published this Friday in the journal The Lancet Planet Health . To arrive at this figure, the researchers start from recommendations contained in a report by the European regional office of the World Health Organization (WHO) that proposes that citizens have access to a green space at a linear distance of 250 meters from your home, the equivalent of a five-minute walk.
Evelise Pereira, researcher at the Barcelona Institute for Global Health (ISGlobal ) and first author of the study, explains that green areas have “benefits for physical and mental health” as determined by many scientific investigations. “Just being able to see a green area can benefit mental health,” adds this researcher. “Green spaces are associated with a decrease in mortality from natural causes,” emphasizes the study, which lists benefits associated with the possibility of doing physical exercise in those areas or the decrease in pollution also linked to the presence of vegetation.
Pereira explains that to carry out their analysis they have taken data from 978 cities and 49 metropolitan areas of more than 50. 000 inhabitants of the 31 selected European countries. Researchers have divided cities into grids of 250 by 250 meters to determine the access to those green areas. To calculate the existing green space in each locality, the study has used the Normalized Difference Vegetation Index (NDVI), an indicator that takes into account any type of vegetation, from tree-lined streets to gardens on private properties, and obtained from satellite images. These data were crossed with those of mortality from natural causes of each city in 2015 to arrive at the deaths that could have been avoided in that year if the recommendation of the WHO access to green areas.
In the thousand European cities analyzed, the number of deaths amounts to 42. 968. In Spain, where a hundred urban agglomerations and cities have been studied, annual deaths are 3. 809. “The impact in Spain is less than in other areas of Europe,” says Pereira. If only the capitals are taken into account, Brussels, Copenhagen, Budapest, Paris and Athens are the cities of the continent with the worst results due to the lack of access to green spaces. Madrid comes out very well and is the fifth with the least negative impacts for this reason. The study includes data from the Madrid metropolitan area and estimates 620 deaths related to the low level of access to green areas.
The metropolitan area of Barcelona, according to the criteria used for the study, is in a much worse situation than the Spanish capital and further from the WHO recommendations. For Barcelona, in addition, a mortality of 924 people is estimated, which means that it accumulates almost the 25% of deaths related to lack of access to green areas in the hundred Spanish cities analyzed. In the case of the Catalan capital, it is harmed by its high population density and the dispersion of parks and green areas, says Pereira.
This researcher also admits that her study has an important limitation: the difficulty in evaluating the positive health effects of the so-called blue zones, that is, rivers, lakes and the coast. “There is not enough evidence to help us quantify these impacts,” he points out regarding the absence of studies in this field.
Based on the data from the study published in the scientific journal The Lancet , the Barcelona Institute for Global Health has developed a classification of urban areas with the worst access to green areas that are furthest from the WHO recommendations.
In the case of Spain, the five cities that fare the worst are Gijón, A Coruña, Cádiz, La Línea de la Concepción, Ferrol, Ceuta, Barcelona and Santander. On the opposite side, Santa Lucía de Tirajana, Valdemoro, Elche, Lorca and Telde are those that are closest to the World Health Organization’s recommendations for access to green areas.
The urban configuration of European cities, with many years of history and high population density, makes access to green areas difficult, explains Pereira. But this researcher bets to look at the examples of cities that are being “redesigned” respecting their essence. “For example, recovering old industrial areas or using public buildings such as schools to increase green areas,” says Pereira, who also highlights as positive some experiences such as superblocks in which they reserve spaces for vegetation.
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