Dynamic Variation of PM2.5 and PM10 Concentrations with Different Distance in Hangzhou Botanical Garden

For studying effect of urban forest on removal of PM2.5 and PM10 and its effective distance, Osmanthus fragrans Garden in Hangzhou Botanical Garden, Zhejiang province, next to Yugu Road was selected for monitoring distribution and variation of PM2.5 and PM10 concentration with 0, 100 and 200 m form the edge to the center of the Garden in the spring and summer in 2018.The results showed that PM2.5 and PM10 concentration in spring was significantly higher than that in summer.In spring, diurnal variation of PM2.5 and PM10 concentration decreased from 9:00 to 17:00, while in the summer, their concentration was higher at 9:00 and 17:00.In spring, PM2.5 was the highest in 100 m from the edge of Garden, PM10 in 0 m.In summer, PM2.5 and PM10 concentration was the highest in 0 m, the lowest in 200 m.The removal efficiency of PM2.5 and PM10 concentrations of green space in summer was significantly higher than that in spring (P < 0.05).The maximum removal efficiency of green space on PM2.5 and PM10 was in 200 m in summer.