NAZAR Research Center MANZAR, the Scientific Journal of landscape 2008-7446 18 75 2026 06 22 Numerical Analysis of the Impact of Building Layout Patterns and Elongation in Residential Blocks Adjacent to Traffic Arteries on Outdoor Air Quality between Buildings Numerical Analysis of the Impact of Building Layout Patterns and Elongation in Residential Blocks Adjacent to Traffic Arteries on Outdoor Air Quality between Buildings 26 37 237626 10.22034/manzar.2025.538692.2370 FA Roghayeh Sharifi Department of Architecture, Shi.C., Islamic Azad University, Shiraz, Iran Aliakbar Heidari Faculty of Technical and Engineering, Yasouj University, Yasouj, Iran Hadi Keshmiri Department of Architecture, Shi.C., Islamic Azad University, Shiraz, Iran Ali Shamsodini Department of Architecture, Shi.C., Islamic Azad University, Shiraz, Iran Journal Article 2025 08 04 The circulation of motor vehicles is one of the defining features of urban life in contemporary cities. However, particulate matter produced by fuel combustion in vehicle engines is considered one of the most significant contributors to air pollution in metropolitan areas. These particles are carried by wind into surrounding spaces, leading to a decline in air quality in built environments located adjacent to heavily trafficked urban arteries. It appears that by selecting appropriate building forms in such areas, it is possible not only to improve natural ventilation but also to partially prevent the penetration of pollutants into the open spaces of these complexes. This study investigates the impact of building layout configuration and elongation patterns in residential complexes located near heavily trafficked urban highways on air quality within the open spaces between them. To assess air quality, three parameters were used: wind speed, mean age of air, and the concentration of accumulated pollutants in the central open space between buildings. To extract case-study samples, three building elongation patterns were initially considered: a square pattern, a rectangular pattern elongated perpendicular to the prevailing wind direction, and a rectangular pattern elongated parallel to the prevailing wind direction. Each form was then arranged in six different layout configurations.<br>Ultimately, 18 case-study samples were generated, each containing a fixed central open space of 225 square meters as the study area. All case studies were assumed to be located 35 meters from an urban highway considered as the source of pollutant emissions. The findings indicate that increasing spatial enclosure through a centralized layout pattern in residential complexes, although reducing pollutant concentration in the central open space, significantly decreases ventilation quality in these areas. Additionally, increasing permeability along façades facing pollutant sources can facilitate the transfer of pollutant particles into the open spaces between buildings. Therefore, elongating building blocks perpendicular to the prevailing wind direction is one of the factors that can help prevent pollutants from entering the leeward open spaces behind them. The circulation of motor vehicles is one of the defining features of urban life in contemporary cities. However, particulate matter produced by fuel combustion in vehicle engines is considered one of the most significant contributors to air pollution in metropolitan areas. These particles are carried by wind into surrounding spaces, leading to a decline in air quality in built environments located adjacent to heavily trafficked urban arteries. It appears that by selecting appropriate building forms in such areas, it is possible not only to improve natural ventilation but also to partially prevent the penetration of pollutants into the open spaces of these complexes. This study investigates the impact of building layout configuration and elongation patterns in residential complexes located near heavily trafficked urban highways on air quality within the open spaces between them. To assess air quality, three parameters were used: wind speed, mean age of air, and the concentration of accumulated pollutants in the central open space between buildings. To extract case-study samples, three building elongation patterns were initially considered: a square pattern, a rectangular pattern elongated perpendicular to the prevailing wind direction, and a rectangular pattern elongated parallel to the prevailing wind direction. Each form was then arranged in six different layout configurations.<br>Ultimately, 18 case-study samples were generated, each containing a fixed central open space of 225 square meters as the study area. All case studies were assumed to be located 35 meters from an urban highway considered as the source of pollutant emissions. The findings indicate that increasing spatial enclosure through a centralized layout pattern in residential complexes, although reducing pollutant concentration in the central open space, significantly decreases ventilation quality in these areas. Additionally, increasing permeability along façades facing pollutant sources can facilitate the transfer of pollutant particles into the open spaces between buildings. Therefore, elongating building blocks perpendicular to the prevailing wind direction is one of the factors that can help prevent pollutants from entering the leeward open spaces behind them. http://www.manzar-sj.com/article_237626_e8f646901d982b43f05ea18cfe240b90.pdf