Deposition, abatement and environmental fate of pollutants in urban green ecosystems: suggestions from long-term studies in Siena (Central Italy)

•Organisms in urban soil and walls reveal air pollutant deposition and bioavailability.•Pb is hardly accumulated by soil- and parietal-fauna and poses little health risk.•Airborne metals intercepted by holm oak foliage get bound in soils under canopy.•Quercus ilex, though a VOCs emitter, is the best native tree for Mediterranean towns.