Settling contaminants such as dust can deposit on the surface of leaves from air. Thus, plants are especially useful biological indicators to assess air pollution.The aim of our study was to validate the assessment of air pollution based on deposited dust on tree leaves. In our study we compared different types (d <5-8 µm and d >2-3 µm) of dust contents on leaves of Common Lime (Tilia × europaea) and dust trap in the three summer months of 2018 in the campus of University of Debrecen, Hungary.We found significant differences in the different types of dust between tree leaves and dust trap. In dust trap 95 percentage of all dust content was deposited dust (d <5-8 µm), while in the case of leaves 77 percentage of all dust content was deposited dust (d <5-8 µm). Based on the study of correlation between dust content in leaves and dust trap we found significant positive correlation in the case of deposited dust (d <5-8 µm). Further, significant correlation was not found between leaves and dust trap based on fine particle size (d >2-3 µm) dust content.Our results demonstrated that leaves are useful indicators to assess dust deposition similar to the dust trap. At the same time, our results also indicated that dust washing is continuous from leaves by rain, while dust deposition on the surface of leaves is limited because of the capacity of tree leaves.