Pollutant concentrations are halved by about 17 m from the road edge! So is the latest finding by Prof. Peter Brimblecombe and his group. The pollutant gradient can be described using an analytical dispersion equation that allows for dispersion along the wind direction. The finding has implication on the future park design with emphasis on the separation between park interiors and roads to lower user exposure.

Xing, Y., & Brimblecombe, P. (2018). Dispersion of traffic derived air pollutants into urban parks. Science of the Total Environment, 622, 576-583.