Pollution and Architecture: Variation in Dispersion Conditions at the Neighborhood Scale In Cergy

The increasing densification of buildings in cities impacts the natural dispersion of atmospheric pollutants, thereby increasing residents' exposure to these contaminants. To better understand the effects of urban configuration on air quality, a typomorphological analysis was conducted in three distinct neighborhoods. This analysis focused on key criteria such as building density, urban porosity, street orientation, and the presence of vegetation. These architectural and spatial parameters were correlated with pollution data (NO ₂ , PM ₁₀ , PM _2.5 ) measured using nine fixed sensors, strategically distributed, along with measurements of wind speed, wind direction, and atmospheric pressure. The results underscore the decisive influence of building density and urban porosity on the capacity of urban spaces to either facilitate or hinder the dispersion of gaseous and particulate pollutants. Vegetation, depending on its location and density, also plays a significant modulating role. The orientation of streets relative to prevailing winds, along with their degree of enclosure, shapes the complex mechanisms of pollutant transport, including horizontal and vertical movements as well as the formation of air vortices. A statistical modeling approach employing multiple regression identified and validated the key spatial and environmental factors driving the variability of pollution concentrations within urban areas. Additionally, the application of the Inverse Distance Weighting (IDW) interpolation method to mobile measurement data revealed localized high-pollution zones, particularly at road intersections and in confined urban spaces. These findings provide a robust foundation for guiding urban planning strategies aimed at enhancing the natural ventilation of neighborhoods and minimizing residents' exposure to atmospheric pollutants, thereby contributing to healthier living environments.