Assessment of Plant Species Suitability in Green Walls Based on API, Heavy Metal Accumulation, and Particulate Matter Capture Capacity

Today, one of the most pressing issues confronting the civilized and modern world is air pollution. Particulate matter (PM) is a well-known pollutant that contributes significantly to urban air pollution and has numerous short- and long-term adverse effects on human health. One method of reducing air pollution is to create green spaces, mainly green walls, as a short-term solution. The current study investigated the ability of nine plant species to reduce traffic-related PM using a green wall system installed along a busy road in Mashhad, Iran. The main aims were (1) estimate the tolerance level of plant species on green walls to air pollution using the Air pollution tolerance index (APTI); (2) assess the PM capture on the leaves of green wall species using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis and accumulation of heavy metals using Inductively Coupled Plasma (ICP); (3) select the most tolerance species for reducing air pollution using Anticipated Performance Index (API). The plants' APTI values ranged from 5 to 12. The highest APTI value was found in Carpobrotus edulis and Rosmarinus officinalis, while Kochia Prostrata had the lowest. Among the APTI constituents, leaf water content (R2 = 0.29) and ascorbic acid (R2 = 0.33) had a positive effect on APTI. According to SEM analysis, many PM were adsorbed on the adaxial and abaxial leaf surfaces, as well as near the stomata of Lavandula angustifolia, C. edulis, Vinca minor, and Hylotelephium sp. Based on EDX analysis, carbon and oxygen formed the highest amount (more than 60%) of metals detected in the elemental composition of PM deposited on the leaves of all species. The Sedum reflexum had the highest Cr, Fe, Pb, and As accumulation. The concentrations of all heavy metals studied in green wall plants were higher than in the control sample. Furthermore, the C. edulis is the best plant for planting in industrial, urban areas of the city based on APTI, biological, economic, and social characteristics. It concludes that the use of green walls composed primarily of plants with small leaves can significantly adsorb PM and accumulation of heavy metal.

Sustainability of green walls

Not long ago, the sustainability of buildings was not taken as a design priority, although it was considered to some extent. The required level of sustainability has risen sharply in recent years, buildings are becoming more self-sufficient, environmental friendly and greener. Towards more attention to green sustainable alternatives in architecture, new solutions for sustainability began to be sought, such as the use of vertical and horizontal surfaces of the building for green facades, the use of roofs for roof greenery, as well as introduction of greenery into building in the form of green walls. Along with the introduction of greenery into the interior comes the new necessary technical solutions, thinking about the overall green wall with respect to the indoor environment and building itself as well as new possibilities of using rainwater, beautify the interior, improving the air etc. However, it is important to perceive a green wall as a living element that must be sustainable, and this is what this article is about. The article focuses on the green walls from the point of examining the available information on this subject in domestic as well as in foreign sources. The results of this article can help to improve understanding of various green walls from different perspectives and compare their view on the green wall in terms of sustainability. The paper helps designers and researchers to orientate in the given topic to create an overview of the different options of the current greenery systems.

Spirits of the Great Green Wall in Senegal

This article offers an ethnographic study of the involvement of a controversial modern Japanese religious movement, Sukyo Mahikari, within the state-led pan-African reforestation project known as the Great Green Wall. The author argues that the members’ environmental efforts against desertilcation and climate change bring together so-called ‘religious’ and ‘secular’ actors. She shows how the oflcial recognition of Sukyo Mahikari as a valuable partner of the Ministry of Environment and Sustainable Development of Senegal blurs the boundaries between the political, environmental, and religious spheres thanks to a ‘working misunderstanding’, an expression coined by Marshal Sahlins, thereby overcoming different framings in their relation to nature. This contribution examines the conditions that have facilitated the simultaneous secularization and spiritualization of ecology in the Senegalese context.

Recognising Recognition in Climate Justice

We argue that in order to achieve climate justice, recognition needs to be given more attention in climate research, discourse, and policies. Through the analysis of three examples, we identify formal and discursive recognition as central types of recognition in climate issues, and we show how powerful actors exercise their power in ways that cause climate injustice through formal and discursive misrecognition of poor and vulnerable groups. The three examples discussed are climate mitigation through forest conservation (REDD), the Great Green Wall project in Sahel, and the narrative about climate change as a contributing factor to the Syrian war.