The impact of street canyon morphology and traffic volume on NO2 values in the street canyons of Antwerp

• Published in: Building and environment 2021-06, Vol.197, p.107825, Article 107825
• Main Authors: Voordeckers, D., Meysman, F.J.R., Billen, P., Tytgat, T., Van Acker, M.
• Format: Article
• Language: English
• Subjects: Air pollution; Air quality monitoring; Citizen science; GIS analysis; Street canyon; Urban planning
• ISSN: 0360-1323; 1873-684X
• DOI: 10.1016/j.buildenv.2021.107825

Air pollution remains a major environmental and health concern in urban environments, especially in street canyons that show increased pollution levels due to a lack of natural ventilation. Previous studies have investigated the relationship between street canyon morphology and in-canyon pollution levels. However, these studies are typically limited to the scale of a single street canyon and city-wide assessments on this matter are scarce. In 2018, NO2 concentrations were measured in 321 street canyons in the city of Antwerp (Belgium) as part of the large-scale citizen-science project “CurieuzeNeuzen”. In our research, this data was used to study the correlation between morphological indices (e.g. aspect ratio (AR), lateral aspect ratio (LAR), presence of trees) and the traffic volumes on a city-wide scale. The maximum hourly traffic volume (TVmax) and AR correlated significantly with the measured NO2 values, making them useful indicators for air quality in street canyons. For street canyons with AR > 0.65, a TVmax of 300 vehicles/hour was found as a threshold value to guarantee acceptable air quality. No significant correlations were found for the other parameters. Finally, a number of typical street canyon types were defined, which can be of fundamental interest for further research and spatial policy making. [Display omitted] •Maximum hourly traffic volume and aspect ratio were detected as suitable indicators for NO2 values.•No significant correlations were found between other morphological indices and NO2 values.•When AR > 0.65, TVmax should be below 300 vehicles/hour to guarantee acceptable air quality.•A number of typical street canyon types was detected based on AR and TVmax.