Deposition of Particulate Matter of Different Size Fractions on Leaf Surfaces and in Epicuticular Waxes of Urban Forest Species in Summer and Fall in Beijing, China

This study compared eight species of urban forest trees and one grass species that are commonly cultivated in Olympic park of Beijing city to capture ﬠne, coarse and larger particles from the air during fall and summer. Separate gravimetric analyses were performed to quantify particulate matter (PM) deposited on surfaces and trapped in epicuticular waxes. Signiﬠcant differences were found between the tree species tested. In Fall, PM content of all 3 particle sizes on the leaf surface and in epicuticular wax is definitely higher than in summer. The distribution of different particle size fractions differed between and within species and also between leaf surfaces and in epicuticular waxes. Needleleaves showed absorption of PM (all 3 sizes of dust) higher than broadleaves, shrubs and grass clusters, except for S. japonica with small hairy leaves. PM deposition on leaf surfaces and waxed layers depends on many elements: leaf shape, hairyand rough surfaces, deposition time, rain, wind and urban forest system model.