particulate matter in the industrial-urban environment. These particles are easily detectable by magnetic measurements on the field. In this paper we present a multidisciplinary mineralogical and magnetic study on some samples directly or closely associated with their pollution sources. Detailed mineralogical investigations (XRD, SEM-EDX, WDX, ATEM) and special magnetic measurements (mass susceptibility, Curie-point, decay rate of the isothermal remanent magnetization in time, frequency dependence of the magnetic susceptibility) were carried out on representative samples. Magnetite was identified as the most important inorganic pollutant using magnetic and mineralogical methods. We found that it had no distinct chemical composition or morphological difference for the different sources, but the extremely small grains are primarily characteristic of traffic. The grain size of magnetite spherules showed decrease among the different sources with the following order: steel factories, combustion plants, traffic. The presence of magnetite as pollutant in the environment can be monitored more easily and costeffectively by magnetic than mineralogical methods. Nevertheless, the magnetic methods should be combined with detailed mineralogical investigations on representative samples selected by their magnetic properties, in order to obtain full information about the pollutants, including non-magnetic constituents.  Additionally, the role of different pollution sources have to be estimated by the complex analyses of the different grain sizes of the dust collected regularly for a long time.