Seasonal variations in the amount of black carbon particles deposited on the leaf surfaces of nine Japanese urban greening tree species and their related factors

Relationship between the amount of black carbon particles deposited on the leaf surface and leaf surface traits in nine urban greening tree species

To select urban greening tree species suitable for the purification of the atmosphere polluted by black carbon (BC) particles, it is necessary to clarify the determinants of the amount of BC particles deposited on the tree leaves. In the present study, we investigated the relationship between the amount of BC particles that were deposited from the atmosphere and firmly adhered to the leaf epicuticular wax, and leaf surface traits in seedlings of nine tree species grown for two years under natural conditions (Fuchu, Tokyo, Japan). There was a significant interspecific difference in the maximum amount of BC particles deposited on the leaf surface, and the order was as follows: Ilex rotunda > Cornus florida > Osmanthus fragrans > Cornus kousa > Quercus glauca ≒ Quercus myrsinifolia > Magnolia kobus ≒ Zelkova serrata ≒ Styrax japonicus. In the nine tree species, significant highly positive correlations were observed between the amount of BC particles deposited on the leaf surface, and the hydrophobicity of leaf epicuticular wax determined by its chemical composition. Therefore, we concluded that the hydrophobicity of leaf epicuticular wax is an important determinant of the amount of BC particles deposited on the leaf surface of urban greening tree species.