[Dust removal effect of urban tree species in Harbin]

Dust removal by plants was proposed as an important basis of designing urban green space system for future urbanization. Dust removal measurement and leaf surface electron-microscopic scanning were taken for 28 tree species in Harbin city. The results showed that there were obviously different effects of dust removal among different tree species. Picea koraiensis and Juniperus rigida were the ideal conifers for dust removal, and their dust removal abilities were 5.7 g.m-2 and 4.4 g.m-2 after 4 weeks, respectively. Populus alba x berolinensis, Lonicera maackii, and Prunus maackii were the ideal deciduous tree species, and their dust removal abilities were respectively 1.9 g.m-2, 2.0 g.m-2, and 2.45 g.m-2 after 2 weeks. Observation under electronic microscope showed that tree species, having deep channels or dense hair on leaf surface had greater effects of dust removal, while tree species, which had strumose projections on leaf surface, had weaker effects. Different modes of dust removal by plants were also discussed.