Green walls an efficient solution for hygrothermal, noise and air pollution control in the buildings

摘要

A building façade is considered to form the first line of protection against adverse climate and environmental conditions in an urban area, such as wind and rain, leading it to be affected and eventually damaged by continued and direct interaction.Furthermore, the increasing ecological and environmental concerns, due to the global warming associated with air and noise pollution, is proved to be linked to the small quantity of vegetation and green areas in urban environments and to technological development. Depending on that, new approaches to improve the environment quality in urban areas started to be developed. One of these approaches is Vertical and Horizontal Gardens, which are taking increasing roles in the recent years.Historically, vertical gardens were the starting point for considering the possibility of growing plants on vertical surfaces and some examples are dated back to 2000 years in Mediterranean regions. Green walls were first used in buildings for simply decorative purposes in many cities of Europe and north America in the 19th century. However, the environmental control value of the green walls in Europe was not noticed until 1980s, where a lot of programs and studies recognized their ability to mitigate particulatematter, reduce noise and provide cooling effects leading to the development of a lot of projects that promoted the usages of green walls.The aim of this paper is to evaluate the efficiency of green walls regarding their ability to mitigate environmental conflicts, taking in consideration the different methods of implementation and their respective advantages and disadvantages.This study systemically reviews recent researches on nature-based solutions namely green walls. Followed by an analysis of the environmental properties of different models of solutions, and an analysis of the costs and the average payback periods. The results of the review can provide a feedback of the most efficient green solutions that could offer good environmental quality with economic advantages.The first part of the paper provides an overall introduction considering the green walls and their implementing methodologies. While the second part presents the environmental and economic effects of the different vertical greening systems on the envelope of the building compared to common building materials. The final results prove that each system of vertical greening varies depending on the levels of environmental benefits and costs, where some systems are proved to be economically sustainable with good environmental properties while others offer a wider range of plants with several implementation methods making them easier