Relationships Between Leaf Exposure Time to Air Pollution and Metal and Particulate Matter Accumulation for Holm Oak Leaves

Plants play a fundamental role by intercepting air particulate matter (PM) and improving air quality. The link between the accumulation of pollutants and the leaf exposure time to air pollution remains unclear as it depends on different factors. The aim of this study is to test if the metal and PM accumulation in holm oak leaf is linked to exposure time to air pollution. For this study, 1- (1y) and 2-year (2y) old holm oak leaves were sampled in an urban area near Naples. Those leaves were analyzed to measure the amount of particulate matter (PM2.5–10 and PM>10) and the Cr, Cu, Mn, and Ni metal concentrations. The results displayed that leaf Cr, Cu, and Mn accumulation are linked to exposure time, whereas leaf PM deposit was not directly linked to the exposure time. PM deposit on leaves could be influenced by rainfall events or by the saturation of leaves’ surface.