Urban forests and parks, besides a recreation function, play significant role in pollution removal by tree canopies. Main sources of dust emissions in cities are industry (steelworks, power plants, coking plants, cement plants) and traffic. The most of dusts, stored in tree crowns, are deposited on soil surface as litterfall (leaves, needles) or are washed into soil by stemflow and throughfall. However, certain amount of dusts can be released into atmosphere as secondary dust emission. The presented studies were conducted on areas of four urban parks and both magnetic and chemical analyses of topsoil were employed. Results show topsoil contamination by heavy metals in urban parks and cumulative role of vegetations (trees) in processes of distribution of air pollution into soil surface. Magnetic susceptibility measurements allow for discrimination of areas for being the potential sources of secondary dust emission in urban parks.