German start-up CityTrees has created massive vertical planter boxes filled with air-filtering plants to improve air quality in urban areas. The planters are called CityTrees and offer the environmental benefits of 6.5 million conventional trees, but at 5% of the associated cost and with 5% less space required. Each CityTree is also equipped with a digital screen to allow the space to be used for advertising. Hong Kong , Dresden , Hong Kong and Dresden are among the handful of cities currently using CityTrees .
German start-up Green City Solutions has created massive vertical planter boxes filled with air-filtering plants to improve air quality in urban areas. The planters are called CityTrees and offer the environmental benefits of up to 275 conventional trees, but at 5% of the associated cost and with 99% less space required. Each CityTree is also equipped with a digital screen to allow the space to be used for advertising. Hong Kong, Oslo, Paris and Dresden are among the handful of cities currently using CityTrees.