More greenery in cities leads to fewer deaths

Parks, botanical gardens and other greenery are not only pleasant to live in, they also have a direct effect on health. The more greenery in the immediate vicinity, the healthier and longer life.

– For example, there is a very clear link between the proximity of green areas and the number of heart attacks, says Patrik Grahn, professor of landscape architecture at the Swedish University of Agricultural Sciences (SLU).

Researchers from Spain’s Barcelona Institute for Global Health have now ranked 1,000 European cities based on the cities’ total greenery, vegetation type and residents’ access to green areas.

In the current study, presented in the Lancet Planetary Health, the researchers relied on the World Health Organization’s recommendation that the green area in question should be a minimum of 0.5 hectares (100×50 meters) and no more than 300 meters from their own home, a limit that Patrik Grahn helped forward.

– If the greenery is further away, you don’t go out very often. That correlation is very strong, he says.

In the current ranking, which includes 13 Swedish cities, the researchers used two measures to calculate how “green” the cities are. One is a kind of “vegetation index” in which satellite maps, among other things, measure the total greenery in a city.

– This index also includes private gardens, says Mark Nieuwenhuijsen, professor of environmental epidemiology and lead author of the current paper.

The second measure is the proportion of the urban area that consists of greenery to which the public has access, such as a park. The researchers then calculated how many deaths per year could have been prevented if all the inhabitants of a city had lived according to the WHO recommendation.

– We have used a number of different epidemiological studies and parameters to estimate how many cases of premature death could be prevented if cities adhered to the WHO guidelines for all residents, says Mark Nieuwenhuijsen.

The starting point was 1,000 cities, but because many cities merged into one another, not least in the metropolitan region, the list the researchers present consists of 866 cities.

The study shows that if all cities followed the WHO recommendation, 42,968 cases of premature death could be prevented each year.

– There are quite a few lives, precisely because the cities have little or no greenery, says Mark Nieuwenhuijsen.

In the current review, the researchers placed the least green cities at the top and the greenest at the bottom. All Swedish cities, except Malmö, do well with placements of 663 or less.

The greenest of all is Gothenburg, which comes in 842 out of 866. Almost the greenest in all of Europe, in other words. According to the researchers, 48.5 percent of Gothenburg consists of green areas and two-thirds of Gothenburgers live in areas that meet the WHO recommendation. However, if everyone had done that, 14 cases of premature death per year could have been prevented.

Shortly after Gothenburg, Lund (position 836) is closely followed by Borås (835). Stockholm finishes in 707th place, while Örebro and Västerås finish in 686 and 663 respectively.

Malmö stands out, whether you measure the total green space or the proximity of public green spaces. This may be due to a method error that researchers are well aware of. A weakness of their method is that it does not take into account so-called blue areas, ie seas, lakes and other watercourses.

– That could be an explanation, since Malmö is on the water. On the other hand, 74 percent of Malmö’s residents live in areas that do not meet the WHO recommendation, which is a fairly large proportion. There is certainly a lot of greenery in other places in Malmö, but it doesn’t matter much if that’s not where people live, says Mark Nieuwenhuijsen.

If that had been the case, 29 deaths could have been prevented, the study shows.

The greenest of all cities is Paredes in Portugal, while Cadiz in Spain is the worst. In the latter, only seven percent of the area consists of public green spaces, while almost none of the city residents have such an area nearby.

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Winston Ferguson

"Total travelaholic. Subtly charming zombie geek. Friend of animals everywhere. Music buff. Explorer. Tv junkie."

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