UA: 83% of streets in Antwerp are ‘street canyons’
“Almost all the streets in the city center of Antwerp are highly polluted.” That is one of the first conclusions of a study organized by the Antwerp University. Antwerp has a lot of densely populated streets with high buildings – the so-called ‘street canyons’ – where pollution is ‘trapped’.
The study started in 2018 and will take four years. The main goal of it was to check how the air in the city could be cleaned. The study focuses on improving wind flows in the streets. It also analyzes the use of chemical house front covering materials to transform polluted air into harmless substances.
Voordeckers also mapped the ‘street canyons’ of Antwerp, Paris, and London. “We developed a method that allows us to calculate a height-width proportion per street segment of five meters.” Apparently, Paris and London have a similar level of pollution.
According to this way of ‘street mapping’, the researchers saw that 83% of all streets between the Antwerp ring road and the river Scheldt are street canyons. The high buildings cause a lack of ventilation and pollution is ‘trapped’. The effect is mainly seen in the lower parts of the streets, precisely at pedestrian’s height.
“Due to the lack of ventilation, air pollution is peaking,” Voordeckers continues. “Those peaks are almost as high as in the busy streets of the town center or on the ring road, where 5 000 cars per hour pass. A similar conclusion was shown earlier by the CurieuzeNeuzen research last year.”
The CurieuzeNeuzen initiative was the largest ‘civil research project ever’ in Flanders, in which 20.000 volunteers participated to measure the air quality at home. The project was an initiative of newspaper De Standaard in cooperation with the Antwerp University and the Flemish Environmental Association (Vlaamse Milieu Maatschappij, VMM), Hiva and Vito.
Voordeckers also estimated the impact of the low-emission zone. “Due to the many street canyons, the low-emission zone does not have the optimal effect. Still, reducing emissions is a positive first step. Although it is clear that additional measures will be necessary. One of those measures could be reconsidering urban development.”
Different heights of buildings could create more turbulence, for instance, bringing cleaner air from the higher layers of air to the streets.
The study also showed that the polluted air remains caught under canopies of terraces, balconies, or in bus or streetcar shelters. “So, it is clear that there is a need for another approach and design,” Voordeckers concludes. “Cities will soon follow the example of Hongkong, where urban development imposes strict directions for better ventilation.”