Many urban Environments are continuously exposed to high concentration of particulate pollutants. Leaf saturation isothermal remanent magnetisation (SIRM) is known as a good proxy of atmospheric particulate matter (PM) concentration. This study assessed leaf SIRM of tree species with different leaf surface characteristics at high spatial resolution. First, leaf SIRM of co-located species was compared. Second, leaf SIRM was assessed between contrasting land use classes. Third, the spatial variability of leaf SIRM was explained by tree species, sampling height, distance to the nearest road and its traffic intensity and tram frequency. The results showed that the highest SIRM values were observed for species with ridged leaf surface (i.e. C. betulus) and hairy leaf (hairy Tilia sp.), and the lowest for the non-hairy Tilia sp. leaves. We found that the leaf SIRM was significantly influenced by tree species, distance to the nearest road and its traffic intensity and tram frequency. The SIRM significantly increased with increasing traffic intensity and tram frequency and by decreasing distance to the nearest road. It was concluded that leaf SIRM depends on leaf surface structure and particulate pollution level and is a good bio-indicator for monitoring spatial variation of magnetic particles in urban environments.
Biomagnetic; urban; tree leaves; particulate matter; traffic;