Confined-air quality based on the geometric efficiency of urban outdoor spaces. Cases study

Abstract

ABSTRACTKnowledge of how the airflow in enclosed outdoor spaces is confined by the geometric construction and atmospheric conditions of buildings will help to illustrate the airflow behaviour patterns among different models. These models recreate ideal architectural types in the urban fabric. From the analysis of the behaviour of air within such confined space, patterns can be defined that relate design to the impact on the air quality in courtyards, street canyons or crossings. Geometric efficiency is a concept by which such patterns can be objectively assessed, and that can be used to improve the design of outdoor spaces in relation to buildings. The aim of the study focuses on evaluating the efficiency of ventilation into confined outdoor spaces. Comparing obtained efficiencies will identify the conditions of the airflow among the architectural design. This comparison can show how geometry and shape modify the behaviour of confined air. Obtained results allow checking the airflow parameters that affect air quality distribution around buildings and inside the confined outdoor spaces between constructions. Direct exposure of air within the confined space to the airflow influence may lead to improving the efficiency of outdoor ventilation. It can reach values between 320% and 460% among similar spaces modifying exposure.