Barcelona has a plan to implement green corridors throughout the city to increase the amount of greenery in public spaces. A health impact assessment led by the Barcelona Institute for Global Health (ISGlobal) has concluded that this plan could result in a “considerable reduction” in mental disorder cases in adult residents, as well as direct and indirect costs associated with mental health cases. The study estimates that mental health disorders account for more than 30% of the global burden of disease.
Scientific evidence shows that green spaces benefit overall health, and mental health in particular, by decreasing exposure to air pollution, noise, and heat, reducing stress and facilitating restorative processes in the body, and encouraging physical activity and social interaction.
The researchers obtained data from a previous study that quantified the land area allocated for green space and the degree of greenery throughout the city in 2015. They then calculated the increase in green space that the implementation of the Green Axes plan would produce across the entire city. Data on the mental health of the population were obtained from the Barcelona Health Survey (2016-2017).
The findings showed that, if fully implemented, the Green Axes plan would result in a 5.67% citywide increase in green space, primarily in residential areas. This increase in vegetation in the second largest city in Spain would lead to the prevention of 14% of cases of self-perceived poor mental health, 13% of visits to mental health specialists and cases of antidepressant use, and 8% of cases of tranquilliser use each year. The researchers further concluded that these mental health benefits for the population would translate into annual savings of €45 million in direct and indirect mental health costs.
“Although our study evaluated the potential impact of the Green Axes plan, the results do not apply exclusively to Barcelona,” commented Mark Nieuwenhuijsen, Director of the Urban Planning, Environment and Health Initiative at ISGlobal. “Any action in any city that leads to an increase in the amount of green space near people’s homes should lead to improvements in the mental health burden across the population.”