Impact of Balcony Depth and Position on Indoor Air Quality of Apartments Located Along Urban Traffic Corridors

Zare, Mohammad Ali; Tavakoli Kazeroni, Mehdi; Paknejadi, Abdolhossein

doi:10.22034/ijumes.2025.2069473.1322

Impact of Balcony Depth and Position on Indoor Air Quality of Apartments Located Along Urban Traffic Corridors

Document Type : Case Study

Authors

Mohammad Ali Zare ¹

Mehdi Tavakoli Kazeroni ²

Abdolhossein Paknejadi ³

¹ Department of Architecture, Yas.,C., Islamic Azad University, Yasuj, Iran

² Department of Architecture Engineering, Shi.,C., Islamic Azad University, Shiraz, Iran

³ Department of Civil Engineering, Yas.,C., Islamic Azad University, Yasuj, Iran

10.22034/ijumes.2025.2069473.1322

Abstract

Today, traffic-related pollution in cities has become a fundamental problem, especially in large urban areas. Balcony characteristics, including shape, depth, length, height of the parapet, balcony position, and so on, have different effects on ventilation quality and the concentration of pollutants entering the building. This study evaluates the role of two variables, balcony depth and its placement, on indoor air quality. For this purpose, 12 buildings with different balcony depths and placements near a metropolitan highway were chosen as case studies and simulated using CFD. The balcony placement in the case studies includes three balcony patterns: facing the prevailing wind, facing away from the prevailing wind, and on both faces; in each pattern, four depths from 0.5 meters to 2 meters were considered for the balconies. This study employs three-dimensional steady RANS equations combined with the k-ω turbulence model to solve the equations. The results show that balconies generally reduce both wind speed and the ingress of pollutants into the indoor space compared with buildings without balconies; however, increasing balcony depth on the windward side decreases the incoming wind speed but increases the concentration of pollutants entering the building. Therefore, changes in balcony depth within this range have little effect on airflow speed or pollutant concentration entering the building; ultimately, employing balconies on both the windward and leeward sides markedly reduce wind speed and pollutant concentrations entering the building, and increasing balcony depth on this side decreases the incoming wind speed while increasing the pollutant concentration entering the building.

Highlights

Traffic-related pollution in cities is a fundamental problem, with vehicle exhaust spreading pollutants into surrounding spaces and contaminating them, especially along main traffic arteries.
The study evaluates the role of two balcony characteristics, depth and placement, on indoor air quality using 12 case-study buildings near a metropolitan highway and CFD simulations.
Balcony patterns investigated include facing the prevailing wind, facing away from the wind, and both faces, with balcony depths ranging from 0.5 to 2 meters.
The results show that balconies generally reduce wind speed and pollutant ingress compared to buildings without balconies, but deeper balconies on the windward side reduce wind speed while increasing pollutant concentration indoors.
Balconies on the leeward side slightly reduce wind speed and pollutant concentrations, and employing balconies on both windward and leeward sides markedly reduces both wind speed and pollutant concentrations, with deeper depths on this combined side further decreasing wind speed but increasing pollutant concentration.

Keywords

Balcony depth

balcony location

CFD method

indoor air quality

NO2 pollutant concentration

Ahmed, F., & Hossain, M. N. (2019) 'The impact of building design on energy consumption in tropical climates: A case study in Dhaka', Building and Environment, 151, pp. 133–145.
Bakhtiari Manesh, M. and Bamian, M.R. (2023), Evaluating the Meaning-Making Principles of Modern Balconies, Interaction Between Indoor and Outdoor of Urban Houses in Kermanshah, Architecture and Urban Planning Armanshahr, 42: 31-46.
Coelho, S., Ferreira, J., Rodrigues, V., & Lopes, M. (2022). Source apportionment of air pollution in European urban areas: Lessons from the ClairCity project. Journal of Environmental Management, 320, 115899. https://doi.org/https://doi.org/10.1016/j.jenvman.2022.115899
Cui, D., Li, X., Du, Y., Mak, C. M., & Kwok, K. (2020). Effects of envelope features on wind flow and pollutant exposure in street canyons. Building and Environment, 176, 106862.
Di Sabatino, S., Buccolieri, R., & Kumar, P. (2018). Spatial Distribution of Air Pollutants in Cities BT - Clinical Handbook of Air Pollution-Related Diseases (F. Capello & A. V. Gaddi (eds.); pp. 75–95). Springer International Publishing. https://doi.org/10.1007/978-3-319-62731-1_5
Hang, J., Wang, Q., Chen, X., Sandberg, M., Zhu, W., Buccolieri, R., & Di Sabatino, S. (2015). City breathability in medium density urban-like geometries evaluated through the pollutant transport rate and the net escape velocity. Building and Environment, 94, 166–182. https://doi.org/https://doi.org/10.1016/j.buildenv.2015.08.002
Harris RI, Deaves DM. The structure of strong winds. Wind engineering in the eighties. In: In: Proceedings of the CIRIA Conference, Construction Industry Research and Information Association; 1981.
Heidari, A., Peyvastehgar, Y., Eskandari, H., & Mansourian, E. (2025). The effect of balcony configurations on ACH and pollutant concentration in symmetrical and asymmetrical street canyons. Scientific Reports, 15(1), 8894.
Jon, K. S., Jong, S. I., Ri, S. H., Ko, J. Y., Ko, S. G., Kim, H., ... & Sin, C. H. (2024). Effects of increasing the degree of building height asymmetry on ventilation and pollutant dispersion within street canyons. Energy and Built Environment, 5(5), 727-740.
Kamali, M., Heidari, A., & Peyvastehgar, Y. (2025). Impact of buildings’ configuration in an urban context on the spread pattern of NO2 and indoor air quality: a CFD simulation. Indoor and Built Environment, 34(1), 162-191.
Kamali, M.; Heidari, A.A.; Piyousegar, Y. (2024), The Effect of Building Form on Wind Speed and Pollutant Concentration in Urban Residential Fabric (Case Study: Zone 1 of Shiraz City), Journal of Urban Planning and Development, Volume 3, Issue 13: 67-82.
Kolarik, B.; Frederiksen, M.; Meyer, H.W.; Ebbehoj, N.E.; Gunnarsen, L. (2014) Investigation of the importance of tertiary contamination,temperature and human behaviour on PCB concentrations in indoor air. Indoor Built Environ, 25, 229–
Li, Z., Xu, J., Ming, T., Peng, C., Huang, J., & Gong, T. (2017). Numerical simulation on the effect of vehicle movement on pollutant dispersion in urban street. Procedia Engineering, 205, 2303-2310.
Li, Z., Zhang, H., Wen, C. Y., Yang, A. S., & Juan, Y. H. (2020). Effects of height-asymmetric street canyon configurations on outdoor air temperature and air quality. Building and Environment, 183, 107195.
Mao, Y., et al. (2017) 'Energy-saving strategies in residential buildings: A review of passive cooling systems', Energy and Buildings, 139, pp. 81–92.
Meciarova, L.; Vilˇcekova, S.; Burdova, E.K.; Kiselak, J. (2017) Factors Effecting the Total Volatile Organic Compound (TVOC) Concentrations in Slovak Households. Int. J. Environ. Res. Public Health, 14, 1443.
Miao, C., Yu, S., Hu, Y., Bu, R., Qi, L., He, X., & Chen, W. (2020). How the morphology of urban street canyons affects suspended particulate matter concentration at the pedestrian level: An in-situ investigation. Sustainable Cities and Society, 55, 102042. https://doi.org/https://doi.org/10.1016/j.scs.2020.102042
Rahman, M. M., et al. (2020) 'Enhancing energy efficiency in residential buildings: A review of passive cooling strategies in Dhaka', Energy Reports, 6, pp. 456–467.
Rahsapaar Monfard, R. and Azmati, Saeed. (2021), Analysis of Wind Behavior in Natural Ventilation and Energy Consumption Reduction in a Residential Building Based on Indigenous Architecture, Case Study: The Effect of Dimensions and Placement of Openings on Natural Ventilation in Amol City, Armanshahr Architecture and Urban Development, 35: 103-114.
Richards, P. . (1989). Computational modelling of wind flows around low rise buildings using PHOENIX. In Report for the ARFC Institute of Engineering Research Wrest ParkPark, Silsoe Research Institute.
Richards, P. J., & Hoxey, R. P. (1993). Appropriate boundary conditions for computational wind engineering models using the k-ϵ turbulence model. Journal of Wind Engineering and Industrial Aerodynamics, 46–47, 145–153. https://doi.org/https://doi.org/10.1016/0167-6105(93)90124-7
Sanchez, B., Santiago, J. L., Martilli, A., Martin, F., Borge, R., Quaassdorff, C., & de la Paz, D. (2017). Modelling NOX concentrations through CFD-RANS in an urban hot-spot using high resolution traffic emissions and meteorology from a mesoscale model. Atmospheric Environment, 163, 155-165.
Santamouris, M., et al. (2021) 'Passive cooling strategies in buildings: A review and a case study', Energy, 230, pp. 120–130.
Sin, C. H., Cui, P. Y., Luo, Y., Jon, K. S., & Huang, Y. D. (2023). CFD modeling on the canyon ventilation and pollutant exposure in asymmetric street canyons with continuity/discontinuity balconies. Atmospheric Pollution Research, 14(1), 101641.
Tominaga, Y., Mochida, A., Yoshie, R., Kataoka, H., Nozu, T., Yoshikawa, M., & Shirasawa, T. (2008). AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings. Journal of Wind Engineering and Industrial Aerodynamics, 96(10), 1749–1761. https://doi.org/https://doi.org/10.1016/j.jweia.2008.02.058
Tong, N. Y., & Leung, D. Y. (2012). Effects of building aspect ratio, diurnal heating scenario, and wind speed on reactive pollutant dispersion in urban street canyons. Journal of Environmental Sciences, 24(12), 2091-2103.
Wong, N. H., et al. (2020) 'Green building and sustainability: A study of energy savings in tropical regions', Building and Environment, 174, pp. 106–118.
Zhao, T., Yang, L., Huang, Q., Zhang, W., Duan, S., Gao, H., & Wang, W. (2020). PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and nitrated-PAHs (NPAHs) emitted by gasoline vehicles: Characterization and health risk assessment. Science of The Total Environment, 727, 138631. https://doi.org/https://doi.org/10.1016/j.scitotenv.2020.138631
Zheng, X., Montazeri, H., & Blocken, B. (2022). Impact of building façade geometrical details on pollutant dispersion in street canyons. Building and Environment, 212, 108746.