Patterns of Dust Retention by Urban Trees in Oasis Cities

Dust pollution in Oasis cities located in arid areas affect resident's body, life and work in long term. The present study examined dust deposition on single leaves of Populus alba L. var. pyramidalis (Bunge) at various heights (1m, 2m, 4m), analysed dust particle size distribution and its contents in arid area city-Aksu, northwest China. The results showed that the amount of dust retained per leaf area of Populus alba L. var. pyramidalis (Bunge) differed significantly between sites, as follows: CAT>IA>P>RA>SFA; Leaves at a height of 1 meter retain the most dust compared with other two heights, as follows: 1m > 2m > 4m. Dust particles larger than PM10 account for more than 90% of all dust particles in all the sites and the dust accumulated on tree leaves is mainly of local urban origin. The variation of heavy metal concentrations in different sites is significant.