This study presents micro-morphological characters and anatomical modifications detected in black pine needles collected from urban polluted areas in order to propose new biomarkers useful in air pollution biomonitoring. The plant samples were collected during the July 2021 from 10 different polluted sites from Bucharest and analyzed using light and scanning electron microscopy. When compared with the samples collected from less polluted sites, needle micromorphology and structure have showed significant alterations such as injured stomatal complex, eroded forms of tubular wax type and complete degradation of wax crystalline structure, raised peristomatal areas, early wax plugs perforations and abnormal epidermal teeth. The loads of heavy metal of samples were assessed by X-ray fluorescence spectrometry and the results showed a positive correlation between structural alteration incidence and needle heavy metal surface depositions.