Effects of vegetation status in urban green spaces on particle removal in a street canyon atmosphere

Green spaces contribute to the removal of significant amounts of air pollutants. This quantitative study, using seasonally monitoring data of Total Suspended Particles (TSP) from green spaces along one street of Pudong, Shanghai, China, demonstrates that vegetation can remove large amounts of TSP. Furthermore, correlation analysis was performed between the vegetation status, measured by canopy density and shelterbelt porosity, and the TSP removal percentage. The results show that (1) vegetation in green spaces greatly contributes to reduce TSP pollution. The width of green spaces along the road should not be smaller than 5 m, with the best width being 10 m, and more evergreen trees should be chosen in order to get a noticeable TSP purification effect; (2) The TSP removal percentage is correlated to the canopy density and inversely correlated to the shelterbelt porosity. The optimum intervals of the canopy density and shelterbelt porosity are 0.70–0.85 and 0.25–0.33, respectively. The proposed optimum intervals can help to estimate the vegetation structure of green spaces and provide technical support for the programming and construction of urban green spaces.