The diffusion of traffic pollutants in different residential blocks based on spatial morphological clustering

Abstract

With urbanization, air quality problems attributed to traffic pollutants have increasingly attracted attention. Residential blocks are the basic spatial units directly related to the quality of the human living environment. Block spatial configuration optimization could effectively reduce the impact of pollutants on humans. The main objective of this study consists of investigating the impact of the different residential block typologies on traffic pollutant diffusion. This paper statistically analyzed various spatial morphological parameters of 236 real residential blocks in Wuhan and divided them into five block types via the k-means clustering method. Then, typical representative blocks of each type were identified. The wind environment and traffic pollutant concentration distribution in five typical representative blocks were simulated via the computational fluid dynamics (CFD) technique, and the influence of the different block types on pollutant diffusion was analyzed. This study found that residential blocks in Wuhan could be better classified according to four types of morphological parameters. The traffic pollutant diffusion routes and distribution in the different type blocks varied. Most pollutants entered the block podium through roof openings. The lateral sides of the adjacent external spaces of street canyons comprised the main channels through which traffic pollutants entered blocks. According to data analysis, the morphological indicators of the block clustering have a certain correlation with the dispersion of traffic pollutants. This paper introduced a novel workflow for traffic pollution studies in actual blocks that can be used as a reference for urban design practitioners.