Urban morphology as a passive strategy in promoting outdoor air quality

Outdoor air quality represents one of the greatest problems facing the world, and influences the indoor environments of residential units, resulting in numerous health risks. Consequently, in addition to architects, planners must consider different urban strategies to limit the pollution risks from vehicular emissions using air pollutant dispersion in order to promote outdoor air quality. Therefore, urban morphology as a passive strategy has gradually reflected new challenge to promote air pollutants dispersion. In this context, this paper aims to investigate the effect of the urban morphology on promoting outdoor air quality at the Mubarak residential blocks in Port Said city. To this aim, four alternatives with various urban forms, and morphological indicators are proposed, and quantitatively assessed to investigate their influence on the dispersion of air pollutants using Ansys Fluent. A transient three-dimensional Computational Fluid Dynamics (CFD) analysis is performed with two specific inflow conditions to assess the performance of each alternative. The results confirmed that the integration of the urban form, and morphological indicators can affect the dispersion of air pollutants. In addition, vertical morphological indicators can dilute the concentrations of air pollutants more so than horizontal indicators over the same time sequence. The proposed alternatives reduced the concentrations of air pollutants by approximately 20–85% compared with the current case, hence promoting both outdoor, and indoor air quality. Such promoting enables residential units to utilize natural ventilation from roadside windows. Moreover, this study will help designers, and policymakers to regrade urban extended in the future from numerous alternatives. •A comprehensive review of promoting outdoor air quality is indicated. .•CFD simulations investigate the performance of four urban morphological alternatives as a passive strategy.•The integration of the urban form, and morphological indicators can impact on air pollutant dispersion in a microclimate.•Four alternatives mitigate air pollutant concentrations by approximately 20–85% compared with the current case.