# Mdpj _sciences_
## 3 Technology and Materials
### Urban Greenery Systems  
To address urban pollution, various studies have explored the use of nature-based greening solutions such as trees, shrubs, and hedges. Urban greenery systems and vegetative environmental buffers are plant-based solutions that function independently of artificial structures like support frames or metal frameworks, serving as barriers and sponges for airborne pollutants. [PERSON] (2018) and [PERSON] et al. (2019) conducted studies to investigate the air-cleaning capacity of urban green infrastructures for particulate matter (PM) and carbon dioxide (CO\({}_{2}\)). These studies tested deciduous trees like maples and beeches, as well as evergreen trees like spruces. Both studies found that these natural filters were effective, with their performance closely linked to climatic factors such as temperature, humidity, and wind speed. Aligning with these findings, [PERSON] et al. (2019) examined the importance of designing urban green systems in relation to environmental conditions. This study evaluated the orientation and placement of trees and shrubs, considering not only their exposure to areas with high pollutant concentrations but also the wind direction to maximize pollutant deposition. [PERSON] et al. (2019) also studied how spatial positioning, characteristics, and types of plant species affect green infrastructure performance, along with the climate in which they are deployed. The goal was to identify the \"optimal model\" to maximize PM absorption. Studies by [PERSON] et al. (2019) and [PERSON] et al. (2019) sought to determine the influence of green infrastructure configuration (trees and hedges) on pollutant removal capacity. [PERSON] et al. (2019) examined the effect of hedge geometry, testing various heights, densities, and depths. [PERSON] et al. (2019) aimed to define the performance differences in urban greenery systems based on tree canopy heterogeneity, the contribution of woody parts to pollutant deposition, and the impact of plant life stages on their mitigation abilities. [PERSON] et al. (2019) and [PERSON] et al. (2019) focused on vegetative environmental buffers (VEBs). These systems use trees and hedges to physically block and intercept pollutant dispersion. They leverage their orientation and arrangement (e.g., in groups or rows) to influence wind direction and speed, thereby affecting the transport of suspended particles. Table 3 summarizes the urban greenery systems assessed in the reviewed studies, detailing the pollutants targeted (PM, CO\({}_{2}\), O\({}_{3}\)), construction types (mostly unspecified as these systems often involve direct planting in urban environments), the variety of vegetation used, and the growing mediums (mostly unspecified due to natural soil usage). The studies include a range of tree species such as _Betula_ spp., _Fagus_ spp., and _Quercus_ spp. (2018), various shrubs and hedges (2019), and specific plant species like _Agave victoriae-regime_ and _Ophiopogon japonicus_(2019). These systems are designed to mitigate urban air pollution through the natural filtration capacities of diverse plant species, contributing to the reduction of particulate matter, CO\({}_{2}\), and O\({}_{3}\). The growing mediums are typically natural soil or unspecified, reflecting the direct integration of these plants into urban landscapes.