# Mdpj _sciences_
## 2 Methodology  
The search for publications to be reviewed in this study was conducted in February 2024, utilizing the Scopus bibliographic database (Figure 1). The search strategy was meticulously designed to identify the scientific literature relevant to the review's focus on the potential of vegetation-based technologies to mitigate environmental pollution from greenhouse gases, VOCs, and atmospheric particulate matter. The search was conducted using a combination of specific keywords to capture a wide range of relevant articles. Keywords included terms such as \"green wall\", \"vertical garden\", \"living wall\", \"urban greenery\", \"green facade\", \"pollution\", \"air\", \"pollutant\", \"carbon\", \"CO\({}_{2}\)\", \"NO\({}_{\text{x}}\)\", \"particulate\", \"VOC\", \"mitigation\", \"system\", \"livestock\", \"sequestration\", and \"biofilter\". These keywords were chosen for the following reasons:  
* \"Green wall\", \"vertical garden\", \"living wall\", \"urban greenery\", and \"green facade\": these terms encompass the various types of vegetation-based systems used in urban environments. * \"Pollution\", \"air\", and \"pollutant\": these terms relate directly to the primary focus of the study, which is air pollution. * \"Carbon\", \"CO\({}_{2}\)\", \"NO\({}_{\text{x}}\)\", \"particulate\", \"VOC\", and \"sequestration\": these terms specify the types of pollutants and processes involved in air quality improvement through green systems. * \"Mitigation\", \"system\", and \"livestock\": these terms help to capture studies focusing on mitigation strategies and specific application environments like livestock buildings. * \"Biofilter\": this term is crucial for identifying studies that use biological systems to filter and purify air. In the initial search phase, articles were identified based on their titles if they directly focused on green systems for pollution reduction, resulting in a total of 108 documents. These titles were then screened to ensure they met this criterion. Articles that clearly did not focus on green systems for pollution reduction were excluded. In the second phase, abstracts of these documents were reviewed to exclude studies that treated the topic superficially or marginally, such as studies on greywater reuse with green walls. This step excluded ten articles, leaving 98 documents. The introduction and conclusion sections of the remaining documents were further analyzed to ensure the studies provided valuable insights into state-of-the-art technologies and materials used in green systems for atmospheric pollution mitigation. Studies were included if they met the following criteria:  
* Discussed experimental performance analyses, methodologies, and instruments used to measure pollutant concentrations. * Quantified the capture of pollutants by botanical biofilters. * Examined the processes, dynamics, and factors influencing plant capacities. To ensure that this review covers the most recent advancements and maintains a high standard of scientific rigor, the following exclusion criteria were applied:  
* Only studies published in the last ten years were included, excluding articles published before 2013. * Only peer-reviewed articles in scientific journals were considered. * Only English-language publications were included to ensure consistency and comprehensibility. * Studies that were too generic or did not focus primarily on green systems, such as those on the life cycle assessment (LCA) of green walls, their thermal properties, or green roof systems, were excluded as they do not pertain to the primary focus of reducing environmental impact through air purification. Figure 1: Diagram visually representing the selection process of articles. Following this rigorous selection process, a total of 44 journal articles were included in this review. These articles were categorized based on the type of green technology and the type of experimental analysis conducted.