Study on Adsorption of TSP, PM1, PM2.5 and PM10 by 8 Greening Tree Species in Hangzhou

In May 2019, leaves of Ginkgo biloba, Malus spectabilis, Cerasus×yedoensis, Yulania denudate, Liquidambar formosana, Cinnamomum camphora, Osmanthus fragrans and Michelia chapensis in 2 places in Hangzhou, Zhejiang province were collected 7 days after rain. Determinations on TSP, PM1, PM2.5, PM10 content were implemented by aerosol regenerator. The result showed that on the terms of per unit leaf area, O. fragrans and M. spectabilis had the strongest ability to absorb TSP and PM10, while C. camphora was the lowest. The ability of M. spectabilis to absorb PM2.5 was significantly higher than that of the other tree species (P < 0.01), followed by O. fragrans, L. formosana and C. camphora were lowest, the PM1 adsorption capacity was similar with that of PM2.5. On the terms of per unit green area, the contents of TSP and PM10 of O. fragrans was significantly higher than that of other tree species. M. spectabilis, C. camphora and G. biloba had lower content. PM2.5 and PM1 adsorption capacity of O. fragrans was the highest, followed by M. spectabilis, L. formosana, M. chapensis, G. biloba, C. × yedoensis. C. camphora and Y. denudate. The proportion of small particles with size of 2.5 μm or less in G. biloba and M. spectabilis was significantly higher than that in the other tree species, while that in C. camphora and Y. denudate was the lowest. The retention of particulate matter per unit leaf area had positive relation with stomatal density, stomatal area and villus density of different tree species. There was a significant positive correlation between stomatal density and TSP content.