Urban Air Quality Improvement: Green Infrastructure and Ecological SynthesisThis briefing document synthesizes data, statistical correlations, and case studies regarding nature-based solutions for urban air quality improvement. It focuses on three primary strategies: industrial green belts, living (green) walls, and the ecological role of spontaneous flora.1. Atmospheric Context: The Urban AirshedAn airshed is a geographical area defined by local topography and meteorology that limits the dispersion of pollutants. Understanding the movement of air masses is critical for modeling urban air quality.Urban Airshed Model (UAM): A three-dimensional grid model used by agencies like the U.S. EPA to simulate physical and chemical atmospheric processes, specifically for managing ozone in urban areas.Uni-directional Impacts:Upwind Airsheds: Represent the origin of pollutants (including secondary pollutants like fine particulate matter and ground-level ozone) affecting a city.Downwind Airsheds:…