The European Environment Agency declares that air pollution is the single largest environmental health hazard in Europe, resulting in a lower quality of life and causing premature deaths and severe diseases. Urban plants are capable of reducing environmental pollution through bioaccumulation of contaminants and can be used as
bioindicators in heavy metal (HMs) and rare earth elements (REEs) airborne pollution. Therefore, the main objective of the research was to evaluate the bioaccumulation of HMs and REEs in leaves of six tree species (Populus nigra L., Populus tremula, Populus x Canadensis Moench, Betula pendula Roth, Fraxinus
excelsior L.and Aesculus hippocastanum L.) from Bucharest.