Medellin is home to more than 2.5 million people. The city is the second largest in Colombia and until recently, the streets of the agglomeration looked like all those in other big cities: a lot of concrete and very little greenery. That all changed in 2016, when the "green corridors" project was launched.

The beginning of the "green corridors" project is linked to the fight for a better environment with cleaner air and lower temperatures. Since 2016, 30 avenues have been created in Medellin, linking vertical gardens, parks, forests, streams, lakes and green roadsides. Initially, the "green corridors" involved planting 12,500 trees in parks and along roadsides, as well as 120,000 plants.

By 2021, a total of 880,000 trees and 2.5 million smaller plants were planted in Medellin. The project initially cost US $16.3 million, while annual maintenance of the green spaces in 2022 amounted to US $625,000.

The first effects of the "green corridors" are already visible. The temperature in the city is dropping and the air is cleaner, however there are currently no studies indicating exactly how much the air quality in Medellin has improved. Maurício Correa, an environmental engineering researcher at the University of Antioquia in Colombia, is in the process of conducting a study on air quality in Medellin. The results are expected to be published in the first months of 2024.

According to Maurício Correa, trees planted along green avenues create a barrier against the dust present in the air, thus naturally protecting the environment. "Some species used in the Medellin project were known to be especially efficient at absorbing pollution, such as the mango tree (Mangifera indica)," Correa tells the BBC.

A study co-authored by Maurício Correa was carried out in 2021. From the results obtained, it can be concluded that the Mangifera indica mango is the best plant of the six used in the "green corridors" project. Mangoes have high resistance to polluted environments and also absorb the most PM2.5 dust.

"This plant is very resistant in terms of contamination. Some other plants do not have the same capacity to survive in a pollution zone," says Correa in an interview with the BBC.

In addition to the "green corridors", 124 parks are also part of the project. All with the aim of making Medellin as green as possible. The increase in vegetation in the city is also having a positive impact on increasing the species of animals and insects living in the Medellin area.

Many of the city's residents support the changes taking place in Medellin. Trees and shrubs provide shade and cooling, further enhancing the visual aspect of the city. Although it is currently not possible to talk about specific figures regarding the improvement in air quality, there is no denying the improvement in the quality of life of residents is associated with the increase in the number of plants.

Source: BBC