Green Wall systems: Where do we stand?

In the last few years, the increase of impervious surfaces, due to ongoing urbanization and climate change led several environmental impacts such as: urban heat island effect, air pollution, urban flooding, deterioration of water discharged in the receiving water bodies, and so on. In this context, a sustainable strategy is required, and an innovative solution can be found in the implementation of low impact development (LID) systems as green walls. These sustainable solutions, by reintroducing vegetation in urban area, can partially restore the pre-urbanization situation and mitigate these drastic environmental impacts. To investigate the state of art of these techniques, a deeper overview on the green wall systems was carried out. This analysis was finalized to evaluate the current developed systems in terms of classification, components and benefits in order to establish where do we stand in terms of evolution of these systems and where we are going in terms of new trends and possible future directions.