Urban street canyons with specific structures worsen wind and pollution issues.
The shape of city streets affects how pollution and wind flow. When street canyons are wider than they are tall, a stable vortex forms. Pollutants spread strongest in canyons where buildings on the windy side are taller. Canyons with buildings taller on the sheltered side have weaker pollutant diffusion. Canyons with parallel buildings have the weakest diffusion.
